CVE-2021-47402 (GCVE-0-2021-47402)
Vulnerability from cvelistv5 – Published: 2024-05-21 15:03 – Updated: 2026-08-05 08:47
VLAI
EPSS
VEX
Title
net: sched: flower: protect fl_walk() with rcu
Summary
In the Linux kernel, the following vulnerability has been resolved:
net: sched: flower: protect fl_walk() with rcu
Patch that refactored fl_walk() to use idr_for_each_entry_continue_ul()
also removed rcu protection of individual filters which causes following
use-after-free when filter is deleted concurrently. Fix fl_walk() to obtain
rcu read lock while iterating and taking the filter reference and temporary
release the lock while calling arg->fn() callback that can sleep.
KASAN trace:
[ 352.773640] ==================================================================
[ 352.775041] BUG: KASAN: use-after-free in fl_walk+0x159/0x240 [cls_flower]
[ 352.776304] Read of size 4 at addr ffff8881c8251480 by task tc/2987
[ 352.777862] CPU: 3 PID: 2987 Comm: tc Not tainted 5.15.0-rc2+ #2
[ 352.778980] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
[ 352.781022] Call Trace:
[ 352.781573] dump_stack_lvl+0x46/0x5a
[ 352.782332] print_address_description.constprop.0+0x1f/0x140
[ 352.783400] ? fl_walk+0x159/0x240 [cls_flower]
[ 352.784292] ? fl_walk+0x159/0x240 [cls_flower]
[ 352.785138] kasan_report.cold+0x83/0xdf
[ 352.785851] ? fl_walk+0x159/0x240 [cls_flower]
[ 352.786587] kasan_check_range+0x145/0x1a0
[ 352.787337] fl_walk+0x159/0x240 [cls_flower]
[ 352.788163] ? fl_put+0x10/0x10 [cls_flower]
[ 352.789007] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220
[ 352.790102] tcf_chain_dump+0x231/0x450
[ 352.790878] ? tcf_chain_tp_delete_empty+0x170/0x170
[ 352.791833] ? __might_sleep+0x2e/0xc0
[ 352.792594] ? tfilter_notify+0x170/0x170
[ 352.793400] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220
[ 352.794477] tc_dump_tfilter+0x385/0x4b0
[ 352.795262] ? tc_new_tfilter+0x1180/0x1180
[ 352.796103] ? __mod_node_page_state+0x1f/0xc0
[ 352.796974] ? __build_skb_around+0x10e/0x130
[ 352.797826] netlink_dump+0x2c0/0x560
[ 352.798563] ? netlink_getsockopt+0x430/0x430
[ 352.799433] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220
[ 352.800542] __netlink_dump_start+0x356/0x440
[ 352.801397] rtnetlink_rcv_msg+0x3ff/0x550
[ 352.802190] ? tc_new_tfilter+0x1180/0x1180
[ 352.802872] ? rtnl_calcit.isra.0+0x1f0/0x1f0
[ 352.803668] ? tc_new_tfilter+0x1180/0x1180
[ 352.804344] ? _copy_from_iter_nocache+0x800/0x800
[ 352.805202] ? kasan_set_track+0x1c/0x30
[ 352.805900] netlink_rcv_skb+0xc6/0x1f0
[ 352.806587] ? rht_deferred_worker+0x6b0/0x6b0
[ 352.807455] ? rtnl_calcit.isra.0+0x1f0/0x1f0
[ 352.808324] ? netlink_ack+0x4d0/0x4d0
[ 352.809086] ? netlink_deliver_tap+0x62/0x3d0
[ 352.809951] netlink_unicast+0x353/0x480
[ 352.810744] ? netlink_attachskb+0x430/0x430
[ 352.811586] ? __alloc_skb+0xd7/0x200
[ 352.812349] netlink_sendmsg+0x396/0x680
[ 352.813132] ? netlink_unicast+0x480/0x480
[ 352.813952] ? __import_iovec+0x192/0x210
[ 352.814759] ? netlink_unicast+0x480/0x480
[ 352.815580] sock_sendmsg+0x6c/0x80
[ 352.816299] ____sys_sendmsg+0x3a5/0x3c0
[ 352.817096] ? kernel_sendmsg+0x30/0x30
[ 352.817873] ? __ia32_sys_recvmmsg+0x150/0x150
[ 352.818753] ___sys_sendmsg+0xd8/0x140
[ 352.819518] ? sendmsg_copy_msghdr+0x110/0x110
[ 352.820402] ? ___sys_recvmsg+0xf4/0x1a0
[ 352.821110] ? __copy_msghdr_from_user+0x260/0x260
[ 352.821934] ? _raw_spin_lock+0x81/0xd0
[ 352.822680] ? __handle_mm_fault+0xef3/0x1b20
[ 352.823549] ? rb_insert_color+0x2a/0x270
[ 352.824373] ? copy_page_range+0x16b0/0x16b0
[ 352.825209] ? perf_event_update_userpage+0x2d0/0x2d0
[ 352.826190] ? __fget_light+0xd9/0xf0
[ 352.826941] __sys_sendmsg+0xb3/0x130
[ 352.827613] ? __sys_sendmsg_sock+0x20/0x20
[ 352.828377] ? do_user_addr_fault+0x2c5/0x8a0
[ 352.829184] ? fpregs_assert_state_consistent+0x52/0x60
[ 352.830001] ? exit_to_user_mode_prepare+0x32/0x160
[ 352.830845] do_syscall_64+0x35/0x80
[ 352.831445] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 352.832331] RIP: 0033:0x7f7bee973c17
[
---truncated---
Severity
7.8 (High)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-09-10 15:38 UTC
Assigner
References
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
d39d714969cda5cbda291402c8c6b1fb1047f42e , < 694b0cee7f8546b69a80996a29cb3cf4149c0453
(git)
Affected: d39d714969cda5cbda291402c8c6b1fb1047f42e , < d0d520c19e7ea19ed38dc5797b12397b6ccf9f88 (git) Affected: d39d714969cda5cbda291402c8c6b1fb1047f42e , < dab4677bdbffa5c8270e79e34e51c89efa0728a0 (git) Affected: d39d714969cda5cbda291402c8c6b1fb1047f42e , < d5ef190693a7d76c5c192d108e8dec48307b46ee (git) |
guessed | |
| Linux | Linux |
Affected:
5.3
Unaffected: 0 , < 5.3 (semver) Unaffected: 5.4.151 , ≤ 5.4.* (semver) Unaffected: 5.10.71 , ≤ 5.10.* (semver) Unaffected: 5.14.10 , ≤ 5.14.* (semver) Unaffected: 5.15 , ≤ * (original_commit_for_fix) |
guessed |
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: sched: flower: protect fl_walk() with rcu\n\nPatch that refactored fl_walk() to use idr_for_each_entry_continue_ul()\nalso removed rcu protection of individual filters which causes following\nuse-after-free when filter is deleted concurrently. Fix fl_walk() to obtain\nrcu read lock while iterating and taking the filter reference and temporary\nrelease the lock while calling arg-\u003efn() callback that can sleep.\n\nKASAN trace:\n\n[ 352.773640] ==================================================================\n[ 352.775041] BUG: KASAN: use-after-free in fl_walk+0x159/0x240 [cls_flower]\n[ 352.776304] Read of size 4 at addr ffff8881c8251480 by task tc/2987\n\n[ 352.777862] CPU: 3 PID: 2987 Comm: tc Not tainted 5.15.0-rc2+ #2\n[ 352.778980] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014\n[ 352.781022] Call Trace:\n[ 352.781573] dump_stack_lvl+0x46/0x5a\n[ 352.782332] print_address_description.constprop.0+0x1f/0x140\n[ 352.783400] ? fl_walk+0x159/0x240 [cls_flower]\n[ 352.784292] ? fl_walk+0x159/0x240 [cls_flower]\n[ 352.785138] kasan_report.cold+0x83/0xdf\n[ 352.785851] ? fl_walk+0x159/0x240 [cls_flower]\n[ 352.786587] kasan_check_range+0x145/0x1a0\n[ 352.787337] fl_walk+0x159/0x240 [cls_flower]\n[ 352.788163] ? fl_put+0x10/0x10 [cls_flower]\n[ 352.789007] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220\n[ 352.790102] tcf_chain_dump+0x231/0x450\n[ 352.790878] ? tcf_chain_tp_delete_empty+0x170/0x170\n[ 352.791833] ? __might_sleep+0x2e/0xc0\n[ 352.792594] ? tfilter_notify+0x170/0x170\n[ 352.793400] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220\n[ 352.794477] tc_dump_tfilter+0x385/0x4b0\n[ 352.795262] ? tc_new_tfilter+0x1180/0x1180\n[ 352.796103] ? __mod_node_page_state+0x1f/0xc0\n[ 352.796974] ? __build_skb_around+0x10e/0x130\n[ 352.797826] netlink_dump+0x2c0/0x560\n[ 352.798563] ? netlink_getsockopt+0x430/0x430\n[ 352.799433] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220\n[ 352.800542] __netlink_dump_start+0x356/0x440\n[ 352.801397] rtnetlink_rcv_msg+0x3ff/0x550\n[ 352.802190] ? tc_new_tfilter+0x1180/0x1180\n[ 352.802872] ? rtnl_calcit.isra.0+0x1f0/0x1f0\n[ 352.803668] ? tc_new_tfilter+0x1180/0x1180\n[ 352.804344] ? _copy_from_iter_nocache+0x800/0x800\n[ 352.805202] ? kasan_set_track+0x1c/0x30\n[ 352.805900] netlink_rcv_skb+0xc6/0x1f0\n[ 352.806587] ? rht_deferred_worker+0x6b0/0x6b0\n[ 352.807455] ? rtnl_calcit.isra.0+0x1f0/0x1f0\n[ 352.808324] ? netlink_ack+0x4d0/0x4d0\n[ 352.809086] ? netlink_deliver_tap+0x62/0x3d0\n[ 352.809951] netlink_unicast+0x353/0x480\n[ 352.810744] ? netlink_attachskb+0x430/0x430\n[ 352.811586] ? __alloc_skb+0xd7/0x200\n[ 352.812349] netlink_sendmsg+0x396/0x680\n[ 352.813132] ? netlink_unicast+0x480/0x480\n[ 352.813952] ? __import_iovec+0x192/0x210\n[ 352.814759] ? netlink_unicast+0x480/0x480\n[ 352.815580] sock_sendmsg+0x6c/0x80\n[ 352.816299] ____sys_sendmsg+0x3a5/0x3c0\n[ 352.817096] ? kernel_sendmsg+0x30/0x30\n[ 352.817873] ? __ia32_sys_recvmmsg+0x150/0x150\n[ 352.818753] ___sys_sendmsg+0xd8/0x140\n[ 352.819518] ? sendmsg_copy_msghdr+0x110/0x110\n[ 352.820402] ? ___sys_recvmsg+0xf4/0x1a0\n[ 352.821110] ? __copy_msghdr_from_user+0x260/0x260\n[ 352.821934] ? _raw_spin_lock+0x81/0xd0\n[ 352.822680] ? __handle_mm_fault+0xef3/0x1b20\n[ 352.823549] ? rb_insert_color+0x2a/0x270\n[ 352.824373] ? copy_page_range+0x16b0/0x16b0\n[ 352.825209] ? perf_event_update_userpage+0x2d0/0x2d0\n[ 352.826190] ? __fget_light+0xd9/0xf0\n[ 352.826941] __sys_sendmsg+0xb3/0x130\n[ 352.827613] ? __sys_sendmsg_sock+0x20/0x20\n[ 352.828377] ? do_user_addr_fault+0x2c5/0x8a0\n[ 352.829184] ? fpregs_assert_state_consistent+0x52/0x60\n[ 352.830001] ? exit_to_user_mode_prepare+0x32/0x160\n[ 352.830845] do_syscall_64+0x35/0x80\n[ 352.831445] entry_SYSCALL_64_after_hwframe+0x44/0xae\n[ 352.832331] RIP: 0033:0x7f7bee973c17\n[ \n---truncated---"
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The bug is triggered through local rtnetlink/tc syscalls (sendmsg \u2192 rtnetlink_rcv_msg \u2192 tc_dump_tfilter/tc_del_tfilter \u2192 fl_walk), not via remotely processed packets.\nAC:L - The attacker controls both sides of the race by concurrently dumping and deleting flower filters they created; flower is TCF_PROTO_OPS_DOIT_UNLOCKED so dump and delete can run without full rtnl serialization.\nPR:L - Creating/deleting filters requires CAP_NET_ADMIN via netlink_net_capable, which an unprivileged user obtains in a user+net namespace (unshare -Urn); tc/qdisc in userns is PR:L per guidance.\nUI:N - Exploitation requires only the attacker\u2019s own netlink operations; no victim action is needed.\nS:U - Impact is confined to the local kernel privilege boundary (standard local privilege escalation/DoS); it does not cross VM, IOMMU, or other security authorities.\nC:H - This is a use-after-free of a kmalloc-2k cls_fl_filter; UAF enables reclaim/spray of the freed object and arbitrary read primitives, including via the dump callback path.\nI:H - UAF of the filter object enables heap spraying and write/control-flow hijacking primitives once the freed slot is reclaimed with attacker-controlled data.\nA:H - The UAF produces a kernel oops/KASAN use-after-free (confirmed in the fix commit trace) and can crash or hang the system even without full exploitation."
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"title": "net: sched: flower: protect fl_walk() with rcu",
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"cveId": "CVE-2021-47402",
"datePublished": "2024-05-21T15:03:56.690Z",
"dateReserved": "2024-05-21T14:58:30.816Z",
"dateUpdated": "2026-08-05T08:47:42.173Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2021-47402",
"date": "2026-09-16",
"epss": "0.00244",
"percentile": "0.15784"
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"fkie_nvd": {
"descriptions": "[{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnet: sched: flower: protect fl_walk() with rcu\\n\\nPatch that refactored fl_walk() to use idr_for_each_entry_continue_ul()\\nalso removed rcu protection of individual filters which causes following\\nuse-after-free when filter is deleted concurrently. Fix fl_walk() to obtain\\nrcu read lock while iterating and taking the filter reference and temporary\\nrelease the lock while calling arg-\u003efn() callback that can sleep.\\n\\nKASAN trace:\\n\\n[ 352.773640] ==================================================================\\n[ 352.775041] BUG: KASAN: use-after-free in fl_walk+0x159/0x240 [cls_flower]\\n[ 352.776304] Read of size 4 at addr ffff8881c8251480 by task tc/2987\\n\\n[ 352.777862] CPU: 3 PID: 2987 Comm: tc Not tainted 5.15.0-rc2+ #2\\n[ 352.778980] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014\\n[ 352.781022] Call Trace:\\n[ 352.781573] dump_stack_lvl+0x46/0x5a\\n[ 352.782332] print_address_description.constprop.0+0x1f/0x140\\n[ 352.783400] ? fl_walk+0x159/0x240 [cls_flower]\\n[ 352.784292] ? fl_walk+0x159/0x240 [cls_flower]\\n[ 352.785138] kasan_report.cold+0x83/0xdf\\n[ 352.785851] ? fl_walk+0x159/0x240 [cls_flower]\\n[ 352.786587] kasan_check_range+0x145/0x1a0\\n[ 352.787337] fl_walk+0x159/0x240 [cls_flower]\\n[ 352.788163] ? fl_put+0x10/0x10 [cls_flower]\\n[ 352.789007] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220\\n[ 352.790102] tcf_chain_dump+0x231/0x450\\n[ 352.790878] ? tcf_chain_tp_delete_empty+0x170/0x170\\n[ 352.791833] ? __might_sleep+0x2e/0xc0\\n[ 352.792594] ? tfilter_notify+0x170/0x170\\n[ 352.793400] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220\\n[ 352.794477] tc_dump_tfilter+0x385/0x4b0\\n[ 352.795262] ? tc_new_tfilter+0x1180/0x1180\\n[ 352.796103] ? __mod_node_page_state+0x1f/0xc0\\n[ 352.796974] ? __build_skb_around+0x10e/0x130\\n[ 352.797826] netlink_dump+0x2c0/0x560\\n[ 352.798563] ? netlink_getsockopt+0x430/0x430\\n[ 352.799433] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220\\n[ 352.800542] __netlink_dump_start+0x356/0x440\\n[ 352.801397] rtnetlink_rcv_msg+0x3ff/0x550\\n[ 352.802190] ? tc_new_tfilter+0x1180/0x1180\\n[ 352.802872] ? rtnl_calcit.isra.0+0x1f0/0x1f0\\n[ 352.803668] ? tc_new_tfilter+0x1180/0x1180\\n[ 352.804344] ? _copy_from_iter_nocache+0x800/0x800\\n[ 352.805202] ? kasan_set_track+0x1c/0x30\\n[ 352.805900] netlink_rcv_skb+0xc6/0x1f0\\n[ 352.806587] ? rht_deferred_worker+0x6b0/0x6b0\\n[ 352.807455] ? rtnl_calcit.isra.0+0x1f0/0x1f0\\n[ 352.808324] ? netlink_ack+0x4d0/0x4d0\\n[ 352.809086] ? netlink_deliver_tap+0x62/0x3d0\\n[ 352.809951] netlink_unicast+0x353/0x480\\n[ 352.810744] ? netlink_attachskb+0x430/0x430\\n[ 352.811586] ? __alloc_skb+0xd7/0x200\\n[ 352.812349] netlink_sendmsg+0x396/0x680\\n[ 352.813132] ? netlink_unicast+0x480/0x480\\n[ 352.813952] ? __import_iovec+0x192/0x210\\n[ 352.814759] ? netlink_unicast+0x480/0x480\\n[ 352.815580] sock_sendmsg+0x6c/0x80\\n[ 352.816299] ____sys_sendmsg+0x3a5/0x3c0\\n[ 352.817096] ? kernel_sendmsg+0x30/0x30\\n[ 352.817873] ? __ia32_sys_recvmmsg+0x150/0x150\\n[ 352.818753] ___sys_sendmsg+0xd8/0x140\\n[ 352.819518] ? sendmsg_copy_msghdr+0x110/0x110\\n[ 352.820402] ? ___sys_recvmsg+0xf4/0x1a0\\n[ 352.821110] ? __copy_msghdr_from_user+0x260/0x260\\n[ 352.821934] ? _raw_spin_lock+0x81/0xd0\\n[ 352.822680] ? __handle_mm_fault+0xef3/0x1b20\\n[ 352.823549] ? rb_insert_color+0x2a/0x270\\n[ 352.824373] ? copy_page_range+0x16b0/0x16b0\\n[ 352.825209] ? perf_event_update_userpage+0x2d0/0x2d0\\n[ 352.826190] ? __fget_light+0xd9/0xf0\\n[ 352.826941] __sys_sendmsg+0xb3/0x130\\n[ 352.827613] ? __sys_sendmsg_sock+0x20/0x20\\n[ 352.828377] ? do_user_addr_fault+0x2c5/0x8a0\\n[ 352.829184] ? fpregs_assert_state_consistent+0x52/0x60\\n[ 352.830001] ? exit_to_user_mode_prepare+0x32/0x160\\n[ 352.830845] do_syscall_64+0x35/0x80\\n[ 352.831445] entry_SYSCALL_64_after_hwframe+0x44/0xae\\n[ 352.832331] RIP: 0033:0x7f7bee973c17\\n[ \\n---truncated---\"}, {\"lang\": \"es\", \"value\": \"En el kernel de Linux, se resolvi\\u00f3 la siguiente vulnerabilidad: net: sched: flower: protege fl_walk() con rcu. El parche que refactoriz\\u00f3 fl_walk() para usar idr_for_each_entry_continue_ul() tambi\\u00e9n elimin\\u00f3 la protecci\\u00f3n de rcu de filtros individuales que provoca el siguiente use after free. cuando el filtro se elimina simult\\u00e1neamente. Se corrige fl_walk() para obtener el bloqueo de lectura de rcu mientras se itera y se toma la referencia del filtro y se libera temporalmente el bloqueo mientras se llama a la devoluci\\u00f3n de llamada arg-\u0026gt;fn() que puede dormir. Seguimiento de KASAN: [352.773640] ============================================= ========================== [352.775041] ERROR: KASAN: use-after-free en fl_walk+0x159/0x240 [cls_flower] [352.776304] Lectura de tama\\u00f1o 4 en addr ffff8881c8251480 por tarea tc/2987 [ 352.777862] CPU: 3 PID: 2987 Comm: tc Not tainted 5.15.0-rc2+ #2 [ 352.778980] Nombre de hardware: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13 .0-0-gf21b5a4aeb02-prebuilt.qemu.org 01/04/2014 [352.781022] Seguimiento de llamadas: [352.781573] dump_stack_lvl+0x46/0x5a [352.782332] print_address_description.constprop.0+0x1f/0x140 [ 352.783400] ? fl_walk+0x159/0x240 [cls_flower] [ 352.784292] ? fl_walk+0x159/0x240 [cls_flower] [ 352.785138] kasan_report.cold+0x83/0xdf [ 352.785851] ? fl_walk+0x159/0x240 [cls_flower] [ 352.786587] kasan_check_range+0x145/0x1a0 [ 352.787337] fl_walk+0x159/0x240 [cls_flower] [ 352.788163] ? fl_put+0x10/0x10 [cls_flower] [ 352.789007] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220 [352.790102] tcf_chain_dump+0x231/0x450 [352.790878]? tcf_chain_tp_delete_empty+0x170/0x170 [352.791833]? __might_sleep+0x2e/0xc0 [ 352.792594] ? tfilter_notify+0x170/0x170 [352.793400]? __mutex_unlock_slowpath.constprop.0+0x220/0x220 [352.794477] tc_dump_tfilter+0x385/0x4b0 [352.795262]? tc_new_tfilter+0x1180/0x1180 [352.796103]? __mod_node_page_state+0x1f/0xc0 [352.796974]? __build_skb_around+0x10e/0x130 [ 352.797826] netlink_dump+0x2c0/0x560 [ 352.798563] ? netlink_getsockopt+0x430/0x430 [352.799433]? __mutex_unlock_slowpath.constprop.0+0x220/0x220 [ 352.800542] __netlink_dump_start+0x356/0x440 [ 352.801397] rtnetlink_rcv_msg+0x3ff/0x550 [ 352.802190] ? tc_new_tfilter+0x1180/0x1180 [352.802872]? rtnl_calcit.isra.0+0x1f0/0x1f0 [ 352.803668] ? tc_new_tfilter+0x1180/0x1180 [352.804344]? _copy_from_iter_nocache+0x800/0x800 [352.805202]? kasan_set_track+0x1c/0x30 [ 352.805900] netlink_rcv_skb+0xc6/0x1f0 [ 352.806587] ? rht_deferred_worker+0x6b0/0x6b0 [352.807455]? rtnl_calcit.isra.0+0x1f0/0x1f0 [352.808324]? netlink_ack+0x4d0/0x4d0 [352.809086]? netlink_deliver_tap+0x62/0x3d0 [352.809951] netlink_unicast+0x353/0x480 [352.810744]? netlink_attachskb+0x430/0x430 [352.811586]? __alloc_skb+0xd7/0x200 [ 352.812349] netlink_sendmsg+0x396/0x680 [ 352.813132] ? netlink_unicast+0x480/0x480 [352.813952]? __import_iovec+0x192/0x210 [352.814759]? netlink_unicast+0x480/0x480 [352.815580] sock_sendmsg+0x6c/0x80 [352.816299] ____sys_sendmsg+0x3a5/0x3c0 [352.817096] ? kernel_sendmsg+0x30/0x30 [352.817873]? __ia32_sys_recvmmsg+0x150/0x150 [ 352.818753] ___sys_sendmsg+0xd8/0x140 [ 352.819518] ? sendmsg_copy_msghdr+0x110/0x110 [352.820402]? ___sys_recvmsg+0xf4/0x1a0 [352.821110]? __copy_msghdr_from_user+0x260/0x260 [352.821934]? _raw_spin_lock+0x81/0xd0 [352.822680]? __handle_mm_fault+0xef3/0x1b20 [352.823549]? rb_insert_color+0x2a/0x270 [352.824373]? copy_page_range+0x16b0/0x16b0 [352.825209]? perf_event_update_userpage+0x2d0/0x2d0 [352.826190]? __fget_light+0xd9/0xf0 [ 352.826941] __sys_sendmsg+0xb3/0x130 [ 352.827613] ? __sys_sendmsg_sock+0x20/0x20 [352.828377]? do_user_addr_fault+0x2c5/0x8a0 [352.829184]? fpregs_assert_state_consistent+0x52/0x60 [352.830001]? exit_to_user_mode_prepare+0x32/0x160 [ 352.830845] do_syscall_64+0x35/0x80 [ 352.831445] Entry_SYSCALL_64_after_hwframe+0x44/0xae [ 352.832331] RIP: 0033:0x7f7bee973c1 7 [ ---truncado---\"}]",
"id": "CVE-2021-47402",
"lastModified": "2024-11-21T06:36:04.283",
"published": "2024-05-21T15:15:25.690",
"references": "[{\"url\": \"https://git.kernel.org/stable/c/694b0cee7f8546b69a80996a29cb3cf4149c0453\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/d0d520c19e7ea19ed38dc5797b12397b6ccf9f88\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/d5ef190693a7d76c5c192d108e8dec48307b46ee\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/dab4677bdbffa5c8270e79e34e51c89efa0728a0\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/694b0cee7f8546b69a80996a29cb3cf4149c0453\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\"}, {\"url\": \"https://git.kernel.org/stable/c/d0d520c19e7ea19ed38dc5797b12397b6ccf9f88\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\"}, {\"url\": \"https://git.kernel.org/stable/c/d5ef190693a7d76c5c192d108e8dec48307b46ee\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\"}, {\"url\": \"https://git.kernel.org/stable/c/dab4677bdbffa5c8270e79e34e51c89efa0728a0\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\"}]",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Undergoing Analysis"
},
"nvd": "{\"cve\":{\"id\":\"CVE-2021-47402\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2024-05-21T15:15:25.690\",\"lastModified\":\"2026-08-04T10:17:02.313\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnet: sched: flower: protect fl_walk() with rcu\\n\\nPatch that refactored fl_walk() to use idr_for_each_entry_continue_ul()\\nalso removed rcu protection of individual filters which causes following\\nuse-after-free when filter is deleted concurrently. Fix fl_walk() to obtain\\nrcu read lock while iterating and taking the filter reference and temporary\\nrelease the lock while calling arg-\u003efn() callback that can sleep.\\n\\nKASAN trace:\\n\\n[ 352.773640] ==================================================================\\n[ 352.775041] BUG: KASAN: use-after-free in fl_walk+0x159/0x240 [cls_flower]\\n[ 352.776304] Read of size 4 at addr ffff8881c8251480 by task tc/2987\\n\\n[ 352.777862] CPU: 3 PID: 2987 Comm: tc Not tainted 5.15.0-rc2+ #2\\n[ 352.778980] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014\\n[ 352.781022] Call Trace:\\n[ 352.781573] dump_stack_lvl+0x46/0x5a\\n[ 352.782332] print_address_description.constprop.0+0x1f/0x140\\n[ 352.783400] ? fl_walk+0x159/0x240 [cls_flower]\\n[ 352.784292] ? fl_walk+0x159/0x240 [cls_flower]\\n[ 352.785138] kasan_report.cold+0x83/0xdf\\n[ 352.785851] ? fl_walk+0x159/0x240 [cls_flower]\\n[ 352.786587] kasan_check_range+0x145/0x1a0\\n[ 352.787337] fl_walk+0x159/0x240 [cls_flower]\\n[ 352.788163] ? fl_put+0x10/0x10 [cls_flower]\\n[ 352.789007] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220\\n[ 352.790102] tcf_chain_dump+0x231/0x450\\n[ 352.790878] ? tcf_chain_tp_delete_empty+0x170/0x170\\n[ 352.791833] ? __might_sleep+0x2e/0xc0\\n[ 352.792594] ? tfilter_notify+0x170/0x170\\n[ 352.793400] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220\\n[ 352.794477] tc_dump_tfilter+0x385/0x4b0\\n[ 352.795262] ? tc_new_tfilter+0x1180/0x1180\\n[ 352.796103] ? __mod_node_page_state+0x1f/0xc0\\n[ 352.796974] ? __build_skb_around+0x10e/0x130\\n[ 352.797826] netlink_dump+0x2c0/0x560\\n[ 352.798563] ? netlink_getsockopt+0x430/0x430\\n[ 352.799433] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220\\n[ 352.800542] __netlink_dump_start+0x356/0x440\\n[ 352.801397] rtnetlink_rcv_msg+0x3ff/0x550\\n[ 352.802190] ? tc_new_tfilter+0x1180/0x1180\\n[ 352.802872] ? rtnl_calcit.isra.0+0x1f0/0x1f0\\n[ 352.803668] ? tc_new_tfilter+0x1180/0x1180\\n[ 352.804344] ? _copy_from_iter_nocache+0x800/0x800\\n[ 352.805202] ? kasan_set_track+0x1c/0x30\\n[ 352.805900] netlink_rcv_skb+0xc6/0x1f0\\n[ 352.806587] ? rht_deferred_worker+0x6b0/0x6b0\\n[ 352.807455] ? rtnl_calcit.isra.0+0x1f0/0x1f0\\n[ 352.808324] ? netlink_ack+0x4d0/0x4d0\\n[ 352.809086] ? netlink_deliver_tap+0x62/0x3d0\\n[ 352.809951] netlink_unicast+0x353/0x480\\n[ 352.810744] ? netlink_attachskb+0x430/0x430\\n[ 352.811586] ? __alloc_skb+0xd7/0x200\\n[ 352.812349] netlink_sendmsg+0x396/0x680\\n[ 352.813132] ? netlink_unicast+0x480/0x480\\n[ 352.813952] ? __import_iovec+0x192/0x210\\n[ 352.814759] ? netlink_unicast+0x480/0x480\\n[ 352.815580] sock_sendmsg+0x6c/0x80\\n[ 352.816299] ____sys_sendmsg+0x3a5/0x3c0\\n[ 352.817096] ? kernel_sendmsg+0x30/0x30\\n[ 352.817873] ? __ia32_sys_recvmmsg+0x150/0x150\\n[ 352.818753] ___sys_sendmsg+0xd8/0x140\\n[ 352.819518] ? sendmsg_copy_msghdr+0x110/0x110\\n[ 352.820402] ? ___sys_recvmsg+0xf4/0x1a0\\n[ 352.821110] ? __copy_msghdr_from_user+0x260/0x260\\n[ 352.821934] ? _raw_spin_lock+0x81/0xd0\\n[ 352.822680] ? __handle_mm_fault+0xef3/0x1b20\\n[ 352.823549] ? rb_insert_color+0x2a/0x270\\n[ 352.824373] ? copy_page_range+0x16b0/0x16b0\\n[ 352.825209] ? perf_event_update_userpage+0x2d0/0x2d0\\n[ 352.826190] ? __fget_light+0xd9/0xf0\\n[ 352.826941] __sys_sendmsg+0xb3/0x130\\n[ 352.827613] ? __sys_sendmsg_sock+0x20/0x20\\n[ 352.828377] ? do_user_addr_fault+0x2c5/0x8a0\\n[ 352.829184] ? fpregs_assert_state_consistent+0x52/0x60\\n[ 352.830001] ? exit_to_user_mode_prepare+0x32/0x160\\n[ 352.830845] do_syscall_64+0x35/0x80\\n[ 352.831445] entry_SYSCALL_64_after_hwframe+0x44/0xae\\n[ 352.832331] RIP: 0033:0x7f7bee973c17\\n[ \\n---truncated---\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: net: sched: flower: protege fl_walk() con rcu. El parche que refactoriz\u00f3 fl_walk() para usar idr_for_each_entry_continue_ul() tambi\u00e9n elimin\u00f3 la protecci\u00f3n de rcu de filtros individuales que provoca el siguiente use after free. cuando el filtro se elimina simult\u00e1neamente. Se corrige fl_walk() para obtener el bloqueo de lectura de rcu mientras se itera y se toma la referencia del filtro y se libera temporalmente el bloqueo mientras se llama a la devoluci\u00f3n de llamada arg-\u0026gt;fn() que puede dormir. Seguimiento de KASAN: [352.773640] ============================================= ========================== [352.775041] ERROR: KASAN: use-after-free en fl_walk+0x159/0x240 [cls_flower] [352.776304] Lectura de tama\u00f1o 4 en addr ffff8881c8251480 por tarea tc/2987 [ 352.777862] CPU: 3 PID: 2987 Comm: tc Not tainted 5.15.0-rc2+ #2 [ 352.778980] Nombre de hardware: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13 .0-0-gf21b5a4aeb02-prebuilt.qemu.org 01/04/2014 [352.781022] Seguimiento de llamadas: [352.781573] dump_stack_lvl+0x46/0x5a [352.782332] print_address_description.constprop.0+0x1f/0x140 [ 352.783400] ? fl_walk+0x159/0x240 [cls_flower] [ 352.784292] ? fl_walk+0x159/0x240 [cls_flower] [ 352.785138] kasan_report.cold+0x83/0xdf [ 352.785851] ? fl_walk+0x159/0x240 [cls_flower] [ 352.786587] kasan_check_range+0x145/0x1a0 [ 352.787337] fl_walk+0x159/0x240 [cls_flower] [ 352.788163] ? fl_put+0x10/0x10 [cls_flower] [ 352.789007] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220 [352.790102] tcf_chain_dump+0x231/0x450 [352.790878]? tcf_chain_tp_delete_empty+0x170/0x170 [352.791833]? __might_sleep+0x2e/0xc0 [ 352.792594] ? tfilter_notify+0x170/0x170 [352.793400]? __mutex_unlock_slowpath.constprop.0+0x220/0x220 [352.794477] tc_dump_tfilter+0x385/0x4b0 [352.795262]? tc_new_tfilter+0x1180/0x1180 [352.796103]? __mod_node_page_state+0x1f/0xc0 [352.796974]? __build_skb_around+0x10e/0x130 [ 352.797826] netlink_dump+0x2c0/0x560 [ 352.798563] ? netlink_getsockopt+0x430/0x430 [352.799433]? __mutex_unlock_slowpath.constprop.0+0x220/0x220 [ 352.800542] __netlink_dump_start+0x356/0x440 [ 352.801397] rtnetlink_rcv_msg+0x3ff/0x550 [ 352.802190] ? tc_new_tfilter+0x1180/0x1180 [352.802872]? rtnl_calcit.isra.0+0x1f0/0x1f0 [ 352.803668] ? tc_new_tfilter+0x1180/0x1180 [352.804344]? _copy_from_iter_nocache+0x800/0x800 [352.805202]? kasan_set_track+0x1c/0x30 [ 352.805900] netlink_rcv_skb+0xc6/0x1f0 [ 352.806587] ? rht_deferred_worker+0x6b0/0x6b0 [352.807455]? rtnl_calcit.isra.0+0x1f0/0x1f0 [352.808324]? netlink_ack+0x4d0/0x4d0 [352.809086]? netlink_deliver_tap+0x62/0x3d0 [352.809951] netlink_unicast+0x353/0x480 [352.810744]? netlink_attachskb+0x430/0x430 [352.811586]? __alloc_skb+0xd7/0x200 [ 352.812349] netlink_sendmsg+0x396/0x680 [ 352.813132] ? netlink_unicast+0x480/0x480 [352.813952]? __import_iovec+0x192/0x210 [352.814759]? netlink_unicast+0x480/0x480 [352.815580] sock_sendmsg+0x6c/0x80 [352.816299] ____sys_sendmsg+0x3a5/0x3c0 [352.817096] ? kernel_sendmsg+0x30/0x30 [352.817873]? __ia32_sys_recvmmsg+0x150/0x150 [ 352.818753] ___sys_sendmsg+0xd8/0x140 [ 352.819518] ? sendmsg_copy_msghdr+0x110/0x110 [352.820402]? ___sys_recvmsg+0xf4/0x1a0 [352.821110]? __copy_msghdr_from_user+0x260/0x260 [352.821934]? _raw_spin_lock+0x81/0xd0 [352.822680]? __handle_mm_fault+0xef3/0x1b20 [352.823549]? rb_insert_color+0x2a/0x270 [352.824373]? copy_page_range+0x16b0/0x16b0 [352.825209]? perf_event_update_userpage+0x2d0/0x2d0 [352.826190]? __fget_light+0xd9/0xf0 [ 352.826941] __sys_sendmsg+0xb3/0x130 [ 352.827613] ? __sys_sendmsg_sock+0x20/0x20 [352.828377]? do_user_addr_fault+0x2c5/0x8a0 [352.829184]? fpregs_assert_state_consistent+0x52/0x60 [352.830001]? exit_to_user_mode_prepare+0x32/0x160 [ 352.830845] do_syscall_64+0x35/0x80 [ 352.831445] Entry_SYSCALL_64_after_hwframe+0x44/0xae [ 352.832331] RIP: 0033:0x7f7bee973c1 7 [ 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"redhat_vex": {
"aggregate_severity": "Moderate",
"current_release_date": "2026-08-04T19:56:40+00:00",
"cve": "CVE-2021-47402",
"id": "CVE-2021-47402",
"initial_release_date": "2021-01-01T00:00:00+00:00",
"product_status:known_affected": "28",
"product_status:known_not_affected": "170",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: net: sched: flower: protect fl_walk() with rcu",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-47402.json",
"version": "3"
},
"suse_vex": {
"aggregate_severity": "important",
"current_release_date": "2026-09-15T02:31:06Z",
"cve": "CVE-2021-47402",
"id": "CVE-2021-47402",
"initial_release_date": "2024-05-28T03:34:14Z",
"product_status:known_affected": "269",
"product_status:known_not_affected": "211",
"product_status:recommended": "650",
"source": "SUSE CSAF VEX",
"status": "interim",
"title": "SUSE CVE CVE-2021-47402",
"url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2021-47402.json",
"version": "69"
},
"vulnrichment": {
"containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"https://git.kernel.org/stable/c/694b0cee7f8546b69a80996a29cb3cf4149c0453\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/d0d520c19e7ea19ed38dc5797b12397b6ccf9f88\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/dab4677bdbffa5c8270e79e34e51c89efa0728a0\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/d5ef190693a7d76c5c192d108e8dec48307b46ee\", \"tags\": [\"x_transferred\"]}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2024-08-04T05:39:58.958Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2021-47402\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2024-09-10T15:38:07.154281Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2024-09-11T12:42:18.156Z\"}}], \"cna\": {\"title\": \"net: sched: flower: protect fl_walk() with rcu\", \"metrics\": [{\"cvssV3_1\": {\"version\": \"3.1\", \"baseScore\": 7.8, \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"AV:L - The bug is triggered through local rtnetlink/tc syscalls (sendmsg \\u2192 rtnetlink_rcv_msg \\u2192 tc_dump_tfilter/tc_del_tfilter \\u2192 fl_walk), not via remotely processed packets.\\nAC:L - The attacker controls both sides of the race by concurrently dumping and deleting flower filters they created; flower is TCF_PROTO_OPS_DOIT_UNLOCKED so dump and delete can run without full rtnl serialization.\\nPR:L - Creating/deleting filters requires CAP_NET_ADMIN via netlink_net_capable, which an unprivileged user obtains in a user+net namespace (unshare -Urn); tc/qdisc in userns is PR:L per guidance.\\nUI:N - Exploitation requires only the attacker\\u2019s own netlink operations; no victim action is needed.\\nS:U - Impact is confined to the local kernel privilege boundary (standard local privilege escalation/DoS); it does not cross VM, IOMMU, or other security authorities.\\nC:H - This is a use-after-free of a kmalloc-2k cls_fl_filter; UAF enables reclaim/spray of the freed object and arbitrary read primitives, including via the dump callback path.\\nI:H - UAF of the filter object enables heap spraying and write/control-flow hijacking primitives once the freed slot is reclaimed with attacker-controlled data.\\nA:H - The UAF produces a kernel oops/KASAN use-after-free (confirmed in the fix commit trace) and can crash or hang the system even without full exploitation.\"}]}], \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"d39d714969cda5cbda291402c8c6b1fb1047f42e\", \"lessThan\": \"694b0cee7f8546b69a80996a29cb3cf4149c0453\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"d39d714969cda5cbda291402c8c6b1fb1047f42e\", \"lessThan\": \"d0d520c19e7ea19ed38dc5797b12397b6ccf9f88\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"d39d714969cda5cbda291402c8c6b1fb1047f42e\", \"lessThan\": \"dab4677bdbffa5c8270e79e34e51c89efa0728a0\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"d39d714969cda5cbda291402c8c6b1fb1047f42e\", \"lessThan\": \"d5ef190693a7d76c5c192d108e8dec48307b46ee\", \"versionType\": \"git\"}], \"programFiles\": [\"net/sched/cls_flower.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"5.3\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"5.3\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"5.4.151\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.4.*\"}, {\"status\": \"unaffected\", \"version\": \"5.10.71\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.10.*\"}, {\"status\": \"unaffected\", \"version\": \"5.14.10\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.14.*\"}, {\"status\": \"unaffected\", \"version\": \"5.15\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"net/sched/cls_flower.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/694b0cee7f8546b69a80996a29cb3cf4149c0453\"}, {\"url\": \"https://git.kernel.org/stable/c/d0d520c19e7ea19ed38dc5797b12397b6ccf9f88\"}, {\"url\": \"https://git.kernel.org/stable/c/dab4677bdbffa5c8270e79e34e51c89efa0728a0\"}, {\"url\": \"https://git.kernel.org/stable/c/d5ef190693a7d76c5c192d108e8dec48307b46ee\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnet: sched: flower: protect fl_walk() with rcu\\n\\nPatch that refactored fl_walk() to use idr_for_each_entry_continue_ul()\\nalso removed rcu protection of individual filters which causes following\\nuse-after-free when filter is deleted concurrently. Fix fl_walk() to obtain\\nrcu read lock while iterating and taking the filter reference and temporary\\nrelease the lock while calling arg-\u003efn() callback that can sleep.\\n\\nKASAN trace:\\n\\n[ 352.773640] ==================================================================\\n[ 352.775041] BUG: KASAN: use-after-free in fl_walk+0x159/0x240 [cls_flower]\\n[ 352.776304] Read of size 4 at addr ffff8881c8251480 by task tc/2987\\n\\n[ 352.777862] CPU: 3 PID: 2987 Comm: tc Not tainted 5.15.0-rc2+ #2\\n[ 352.778980] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014\\n[ 352.781022] Call Trace:\\n[ 352.781573] dump_stack_lvl+0x46/0x5a\\n[ 352.782332] print_address_description.constprop.0+0x1f/0x140\\n[ 352.783400] ? fl_walk+0x159/0x240 [cls_flower]\\n[ 352.784292] ? fl_walk+0x159/0x240 [cls_flower]\\n[ 352.785138] kasan_report.cold+0x83/0xdf\\n[ 352.785851] ? fl_walk+0x159/0x240 [cls_flower]\\n[ 352.786587] kasan_check_range+0x145/0x1a0\\n[ 352.787337] fl_walk+0x159/0x240 [cls_flower]\\n[ 352.788163] ? fl_put+0x10/0x10 [cls_flower]\\n[ 352.789007] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220\\n[ 352.790102] tcf_chain_dump+0x231/0x450\\n[ 352.790878] ? tcf_chain_tp_delete_empty+0x170/0x170\\n[ 352.791833] ? __might_sleep+0x2e/0xc0\\n[ 352.792594] ? tfilter_notify+0x170/0x170\\n[ 352.793400] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220\\n[ 352.794477] tc_dump_tfilter+0x385/0x4b0\\n[ 352.795262] ? tc_new_tfilter+0x1180/0x1180\\n[ 352.796103] ? __mod_node_page_state+0x1f/0xc0\\n[ 352.796974] ? __build_skb_around+0x10e/0x130\\n[ 352.797826] netlink_dump+0x2c0/0x560\\n[ 352.798563] ? netlink_getsockopt+0x430/0x430\\n[ 352.799433] ? __mutex_unlock_slowpath.constprop.0+0x220/0x220\\n[ 352.800542] __netlink_dump_start+0x356/0x440\\n[ 352.801397] rtnetlink_rcv_msg+0x3ff/0x550\\n[ 352.802190] ? tc_new_tfilter+0x1180/0x1180\\n[ 352.802872] ? rtnl_calcit.isra.0+0x1f0/0x1f0\\n[ 352.803668] ? tc_new_tfilter+0x1180/0x1180\\n[ 352.804344] ? _copy_from_iter_nocache+0x800/0x800\\n[ 352.805202] ? kasan_set_track+0x1c/0x30\\n[ 352.805900] netlink_rcv_skb+0xc6/0x1f0\\n[ 352.806587] ? rht_deferred_worker+0x6b0/0x6b0\\n[ 352.807455] ? rtnl_calcit.isra.0+0x1f0/0x1f0\\n[ 352.808324] ? netlink_ack+0x4d0/0x4d0\\n[ 352.809086] ? netlink_deliver_tap+0x62/0x3d0\\n[ 352.809951] netlink_unicast+0x353/0x480\\n[ 352.810744] ? netlink_attachskb+0x430/0x430\\n[ 352.811586] ? __alloc_skb+0xd7/0x200\\n[ 352.812349] netlink_sendmsg+0x396/0x680\\n[ 352.813132] ? netlink_unicast+0x480/0x480\\n[ 352.813952] ? __import_iovec+0x192/0x210\\n[ 352.814759] ? netlink_unicast+0x480/0x480\\n[ 352.815580] sock_sendmsg+0x6c/0x80\\n[ 352.816299] ____sys_sendmsg+0x3a5/0x3c0\\n[ 352.817096] ? kernel_sendmsg+0x30/0x30\\n[ 352.817873] ? __ia32_sys_recvmmsg+0x150/0x150\\n[ 352.818753] ___sys_sendmsg+0xd8/0x140\\n[ 352.819518] ? sendmsg_copy_msghdr+0x110/0x110\\n[ 352.820402] ? ___sys_recvmsg+0xf4/0x1a0\\n[ 352.821110] ? __copy_msghdr_from_user+0x260/0x260\\n[ 352.821934] ? _raw_spin_lock+0x81/0xd0\\n[ 352.822680] ? __handle_mm_fault+0xef3/0x1b20\\n[ 352.823549] ? rb_insert_color+0x2a/0x270\\n[ 352.824373] ? copy_page_range+0x16b0/0x16b0\\n[ 352.825209] ? perf_event_update_userpage+0x2d0/0x2d0\\n[ 352.826190] ? __fget_light+0xd9/0xf0\\n[ 352.826941] __sys_sendmsg+0xb3/0x130\\n[ 352.827613] ? __sys_sendmsg_sock+0x20/0x20\\n[ 352.828377] ? do_user_addr_fault+0x2c5/0x8a0\\n[ 352.829184] ? fpregs_assert_state_consistent+0x52/0x60\\n[ 352.830001] ? exit_to_user_mode_prepare+0x32/0x160\\n[ 352.830845] do_syscall_64+0x35/0x80\\n[ 352.831445] entry_SYSCALL_64_after_hwframe+0x44/0xae\\n[ 352.832331] RIP: 0033:0x7f7bee973c17\\n[ \\n---truncated---\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.4.151\", \"versionStartIncluding\": \"5.3\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.10.71\", \"versionStartIncluding\": \"5.3\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.14.10\", \"versionStartIncluding\": \"5.3\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.15\", \"versionStartIncluding\": \"5.3\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2026-08-05T08:47:42.173Z\"}}}",
"cveMetadata": "{\"cveId\": \"CVE-2021-47402\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-05T08:47:42.173Z\", \"dateReserved\": \"2024-05-21T14:58:30.816Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2024-05-21T15:03:56.690Z\", \"assignerShortName\": \"Linux\"}",
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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