Vulnerability-Lookup

GHSA-CH6G-Q299-J266

Vulnerability from github – Published: 2025-01-31 12:33 – Updated: 2025-10-15 15:30

Details

In the Linux kernel, the following vulnerability has been resolved:

pfcp: Destroy device along with udp socket's netns dismantle.

pfcp_newlink() links the device to a list in dev_net(dev) instead of net, where a udp tunnel socket is created.

Even when net is removed, the device stays alive on dev_net(dev). Then, removing net triggers the splat below. [0]

In this example, pfcp0 is created in ns2, but the udp socket is created in ns1.

ip netns add ns1 ip netns add ns2 ip -n ns1 link add netns ns2 name pfcp0 type pfcp ip netns del ns1

Let's link the device to the socket's netns instead.

Now, pfcp_net_exit() needs another netdev iteration to remove all pfcp devices in the netns.

pfcp_dev_list is not used under RCU, so the list API is converted to the non-RCU variant.

pfcp_net_exit() can be converted to .exit_batch_rtnl() in net-next.

[0]: ref_tracker: net notrefcnt@00000000128b34dc has 1/1 users at sk_alloc (./include/net/net_namespace.h:345 net/core/sock.c:2236) inet_create (net/ipv4/af_inet.c:326 net/ipv4/af_inet.c:252) __sock_create (net/socket.c:1558) udp_sock_create4 (net/ipv4/udp_tunnel_core.c:18) pfcp_create_sock (drivers/net/pfcp.c:168) pfcp_newlink (drivers/net/pfcp.c:182 drivers/net/pfcp.c:197) rtnl_newlink (net/core/rtnetlink.c:3786 net/core/rtnetlink.c:3897 net/core/rtnetlink.c:4012) rtnetlink_rcv_msg (net/core/rtnetlink.c:6922) netlink_rcv_skb (net/netlink/af_netlink.c:2542) netlink_unicast (net/netlink/af_netlink.c:1321 net/netlink/af_netlink.c:1347) netlink_sendmsg (net/netlink/af_netlink.c:1891) _syssendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2583) _sys_sendmsg (net/socket.c:2639) __sys_sendmsg (net/socket.c:2669) do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)

WARNING: CPU: 1 PID: 11 at lib/ref_tracker.c:179 ref_tracker_dir_exit (lib/ref_tracker.c:179) Modules linked in: CPU: 1 UID: 0 PID: 11 Comm: kworker/u16:0 Not tainted 6.13.0-rc5-00147-g4c1224501e9d #5 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 Workqueue: netns cleanup_net RIP: 0010:ref_tracker_dir_exit (lib/ref_tracker.c:179) Code: 00 00 00 fc ff df 4d 8b 26 49 bd 00 01 00 00 00 00 ad de 4c 39 f5 0f 85 df 00 00 00 48 8b 74 24 08 48 89 df e8 a5 cc 12 02 90 <0f> 0b 90 48 8d 6b 44 be 04 00 00 00 48 89 ef e8 80 de 67 ff 48 89 RSP: 0018:ff11000007f3fb60 EFLAGS: 00010286 RAX: 00000000000020ef RBX: ff1100000d6481e0 RCX: 1ffffffff0e40d82 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8423ee3c RBP: ff1100000d648230 R08: 0000000000000001 R09: fffffbfff0e395af R10: 0000000000000001 R11: 0000000000000000 R12: ff1100000d648230 R13: dead000000000100 R14: ff1100000d648230 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ff1100006ce80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005620e1363990 CR3: 000000000eeb2002 CR4: 0000000000771ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: ? __warn (kernel/panic.c:748) ? ref_tracker_dir_exit (lib/ref_tracker.c:179) ? report_bug (lib/bug.c:201 lib/bug.c:219) ? handle_bug (arch/x86/kernel/traps.c:285) ? exc_invalid_op (arch/x86/kernel/traps.c:309 (discriminator 1)) ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:621) ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/irqflags.h:42 ./arch/x86/include/asm/irqflags.h:97 ./arch/x86/include/asm/irqflags.h:155 ./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) ? ref_tracker_dir_exit (lib/ref_tracker.c:179) ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:158) ? kfree (mm/slub.c:4613 mm/slub.c:4761) net_free (net/core/net_namespace.c:476 net/core/net_namespace.c:467) cleanup_net (net/cor ---truncated---

Severity

5.5 (Medium)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2025-21677"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-01-31T12:15:28Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\npfcp: Destroy device along with udp socket\u0027s netns dismantle.\n\npfcp_newlink() links the device to a list in dev_net(dev) instead\nof net, where a udp tunnel socket is created.\n\nEven when net is removed, the device stays alive on dev_net(dev).\nThen, removing net triggers the splat below. [0]\n\nIn this example, pfcp0 is created in ns2, but the udp socket is\ncreated in ns1.\n\n  ip netns add ns1\n  ip netns add ns2\n  ip -n ns1 link add netns ns2 name pfcp0 type pfcp\n  ip netns del ns1\n\nLet\u0027s link the device to the socket\u0027s netns instead.\n\nNow, pfcp_net_exit() needs another netdev iteration to remove\nall pfcp devices in the netns.\n\npfcp_dev_list is not used under RCU, so the list API is converted\nto the non-RCU variant.\n\npfcp_net_exit() can be converted to .exit_batch_rtnl() in net-next.\n\n[0]:\nref_tracker: net notrefcnt@00000000128b34dc has 1/1 users at\n     sk_alloc (./include/net/net_namespace.h:345 net/core/sock.c:2236)\n     inet_create (net/ipv4/af_inet.c:326 net/ipv4/af_inet.c:252)\n     __sock_create (net/socket.c:1558)\n     udp_sock_create4 (net/ipv4/udp_tunnel_core.c:18)\n     pfcp_create_sock (drivers/net/pfcp.c:168)\n     pfcp_newlink (drivers/net/pfcp.c:182 drivers/net/pfcp.c:197)\n     rtnl_newlink (net/core/rtnetlink.c:3786 net/core/rtnetlink.c:3897 net/core/rtnetlink.c:4012)\n     rtnetlink_rcv_msg (net/core/rtnetlink.c:6922)\n     netlink_rcv_skb (net/netlink/af_netlink.c:2542)\n     netlink_unicast (net/netlink/af_netlink.c:1321 net/netlink/af_netlink.c:1347)\n     netlink_sendmsg (net/netlink/af_netlink.c:1891)\n     ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2583)\n     ___sys_sendmsg (net/socket.c:2639)\n     __sys_sendmsg (net/socket.c:2669)\n     do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)\n     entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n\nWARNING: CPU: 1 PID: 11 at lib/ref_tracker.c:179 ref_tracker_dir_exit (lib/ref_tracker.c:179)\nModules linked in:\nCPU: 1 UID: 0 PID: 11 Comm: kworker/u16:0 Not tainted 6.13.0-rc5-00147-g4c1224501e9d #5\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014\nWorkqueue: netns cleanup_net\nRIP: 0010:ref_tracker_dir_exit (lib/ref_tracker.c:179)\nCode: 00 00 00 fc ff df 4d 8b 26 49 bd 00 01 00 00 00 00 ad de 4c 39 f5 0f 85 df 00 00 00 48 8b 74 24 08 48 89 df e8 a5 cc 12 02 90 \u003c0f\u003e 0b 90 48 8d 6b 44 be 04 00 00 00 48 89 ef e8 80 de 67 ff 48 89\nRSP: 0018:ff11000007f3fb60 EFLAGS: 00010286\nRAX: 00000000000020ef RBX: ff1100000d6481e0 RCX: 1ffffffff0e40d82\nRDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8423ee3c\nRBP: ff1100000d648230 R08: 0000000000000001 R09: fffffbfff0e395af\nR10: 0000000000000001 R11: 0000000000000000 R12: ff1100000d648230\nR13: dead000000000100 R14: ff1100000d648230 R15: dffffc0000000000\nFS:  0000000000000000(0000) GS:ff1100006ce80000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00005620e1363990 CR3: 000000000eeb2002 CR4: 0000000000771ef0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400\nPKRU: 55555554\nCall Trace:\n \u003cTASK\u003e\n ? __warn (kernel/panic.c:748)\n ? ref_tracker_dir_exit (lib/ref_tracker.c:179)\n ? report_bug (lib/bug.c:201 lib/bug.c:219)\n ? handle_bug (arch/x86/kernel/traps.c:285)\n ? exc_invalid_op (arch/x86/kernel/traps.c:309 (discriminator 1))\n ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:621)\n ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/irqflags.h:42 ./arch/x86/include/asm/irqflags.h:97 ./arch/x86/include/asm/irqflags.h:155 ./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194)\n ? ref_tracker_dir_exit (lib/ref_tracker.c:179)\n ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:158)\n ? kfree (mm/slub.c:4613 mm/slub.c:4761)\n net_free (net/core/net_namespace.c:476 net/core/net_namespace.c:467)\n cleanup_net (net/cor\n---truncated---",
  "id": "GHSA-ch6g-q299-j266",
  "modified": "2025-10-15T15:30:21Z",
  "published": "2025-01-31T12:33:03Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-21677"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1c35a66e2bfea53dea3562b2575ac7fd4c38ee61"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ffc90e9ca61b0f619326a1417ff32efd6cc71ed2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2025-21677 (GCVE-0-2025-21677)

Vulnerability from cvelistv5 – Published: 2025-01-31 11:25 – Updated: 2026-08-05 11:53

Title

pfcp: Destroy device along with udp socket's netns dismantle.

Summary

In the Linux kernel, the following vulnerability has been resolved: pfcp: Destroy device along with udp socket's netns dismantle. pfcp_newlink() links the device to a list in dev_net(dev) instead of net, where a udp tunnel socket is created. Even when net is removed, the device stays alive on dev_net(dev). Then, removing net triggers the splat below. [0] In this example, pfcp0 is created in ns2, but the udp socket is created in ns1. ip netns add ns1 ip netns add ns2 ip -n ns1 link add netns ns2 name pfcp0 type pfcp ip netns del ns1 Let's link the device to the socket's netns instead. Now, pfcp_net_exit() needs another netdev iteration to remove all pfcp devices in the netns. pfcp_dev_list is not used under RCU, so the list API is converted to the non-RCU variant. pfcp_net_exit() can be converted to .exit_batch_rtnl() in net-next. [0]: ref_tracker: net notrefcnt@00000000128b34dc has 1/1 users at sk_alloc (./include/net/net_namespace.h:345 net/core/sock.c:2236) inet_create (net/ipv4/af_inet.c:326 net/ipv4/af_inet.c:252) __sock_create (net/socket.c:1558) udp_sock_create4 (net/ipv4/udp_tunnel_core.c:18) pfcp_create_sock (drivers/net/pfcp.c:168) pfcp_newlink (drivers/net/pfcp.c:182 drivers/net/pfcp.c:197) rtnl_newlink (net/core/rtnetlink.c:3786 net/core/rtnetlink.c:3897 net/core/rtnetlink.c:4012) rtnetlink_rcv_msg (net/core/rtnetlink.c:6922) netlink_rcv_skb (net/netlink/af_netlink.c:2542) netlink_unicast (net/netlink/af_netlink.c:1321 net/netlink/af_netlink.c:1347) netlink_sendmsg (net/netlink/af_netlink.c:1891) ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2583) ___sys_sendmsg (net/socket.c:2639) __sys_sendmsg (net/socket.c:2669) do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) WARNING: CPU: 1 PID: 11 at lib/ref_tracker.c:179 ref_tracker_dir_exit (lib/ref_tracker.c:179) Modules linked in: CPU: 1 UID: 0 PID: 11 Comm: kworker/u16:0 Not tainted 6.13.0-rc5-00147-g4c1224501e9d #5 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 Workqueue: netns cleanup_net RIP: 0010:ref_tracker_dir_exit (lib/ref_tracker.c:179) Code: 00 00 00 fc ff df 4d 8b 26 49 bd 00 01 00 00 00 00 ad de 4c 39 f5 0f 85 df 00 00 00 48 8b 74 24 08 48 89 df e8 a5 cc 12 02 90 <0f> 0b 90 48 8d 6b 44 be 04 00 00 00 48 89 ef e8 80 de 67 ff 48 89 RSP: 0018:ff11000007f3fb60 EFLAGS: 00010286 RAX: 00000000000020ef RBX: ff1100000d6481e0 RCX: 1ffffffff0e40d82 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8423ee3c RBP: ff1100000d648230 R08: 0000000000000001 R09: fffffbfff0e395af R10: 0000000000000001 R11: 0000000000000000 R12: ff1100000d648230 R13: dead000000000100 R14: ff1100000d648230 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ff1100006ce80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005620e1363990 CR3: 000000000eeb2002 CR4: 0000000000771ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> ? __warn (kernel/panic.c:748) ? ref_tracker_dir_exit (lib/ref_tracker.c:179) ? report_bug (lib/bug.c:201 lib/bug.c:219) ? handle_bug (arch/x86/kernel/traps.c:285) ? exc_invalid_op (arch/x86/kernel/traps.c:309 (discriminator 1)) ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:621) ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/irqflags.h:42 ./arch/x86/include/asm/irqflags.h:97 ./arch/x86/include/asm/irqflags.h:155 ./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) ? ref_tracker_dir_exit (lib/ref_tracker.c:179) ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:158) ? kfree (mm/slub.c:4613 mm/slub.c:4761) net_free (net/core/net_namespace.c:476 net/core/net_namespace.c:467) cleanup_net (net/cor ---truncated---

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/1c35a66e2bfea53de…
https://git.kernel.org/stable/c/ffc90e9ca61b0f619…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 76c8764ef36a5d37ea2e551bda28ac7f028383ba , < 1c35a66e2bfea53dea3562b2575ac7fd4c38ee61 (git) Affected: 76c8764ef36a5d37ea2e551bda28ac7f028383ba , < ffc90e9ca61b0f619326a1417ff32efd6cc71ed2 (git)
Linux	Linux	Affected: 6.10 Unaffected: 0 , < 6.10 (semver) Unaffected: 6.12.11 , ≤ 6.12.* (semver) Unaffected: 6.13 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/pfcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "1c35a66e2bfea53dea3562b2575ac7fd4c38ee61",
              "status": "affected",
              "version": "76c8764ef36a5d37ea2e551bda28ac7f028383ba",
              "versionType": "git"
            },
            {
              "lessThan": "ffc90e9ca61b0f619326a1417ff32efd6cc71ed2",
              "status": "affected",
              "version": "76c8764ef36a5d37ea2e551bda28ac7f028383ba",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/pfcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.10"
            },
            {
              "lessThan": "6.10",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.13",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.11",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.13",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npfcp: Destroy device along with udp socket\u0027s netns dismantle.\n\npfcp_newlink() links the device to a list in dev_net(dev) instead\nof net, where a udp tunnel socket is created.\n\nEven when net is removed, the device stays alive on dev_net(dev).\nThen, removing net triggers the splat below. [0]\n\nIn this example, pfcp0 is created in ns2, but the udp socket is\ncreated in ns1.\n\n  ip netns add ns1\n  ip netns add ns2\n  ip -n ns1 link add netns ns2 name pfcp0 type pfcp\n  ip netns del ns1\n\nLet\u0027s link the device to the socket\u0027s netns instead.\n\nNow, pfcp_net_exit() needs another netdev iteration to remove\nall pfcp devices in the netns.\n\npfcp_dev_list is not used under RCU, so the list API is converted\nto the non-RCU variant.\n\npfcp_net_exit() can be converted to .exit_batch_rtnl() in net-next.\n\n[0]:\nref_tracker: net notrefcnt@00000000128b34dc has 1/1 users at\n     sk_alloc (./include/net/net_namespace.h:345 net/core/sock.c:2236)\n     inet_create (net/ipv4/af_inet.c:326 net/ipv4/af_inet.c:252)\n     __sock_create (net/socket.c:1558)\n     udp_sock_create4 (net/ipv4/udp_tunnel_core.c:18)\n     pfcp_create_sock (drivers/net/pfcp.c:168)\n     pfcp_newlink (drivers/net/pfcp.c:182 drivers/net/pfcp.c:197)\n     rtnl_newlink (net/core/rtnetlink.c:3786 net/core/rtnetlink.c:3897 net/core/rtnetlink.c:4012)\n     rtnetlink_rcv_msg (net/core/rtnetlink.c:6922)\n     netlink_rcv_skb (net/netlink/af_netlink.c:2542)\n     netlink_unicast (net/netlink/af_netlink.c:1321 net/netlink/af_netlink.c:1347)\n     netlink_sendmsg (net/netlink/af_netlink.c:1891)\n     ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2583)\n     ___sys_sendmsg (net/socket.c:2639)\n     __sys_sendmsg (net/socket.c:2669)\n     do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)\n     entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n\nWARNING: CPU: 1 PID: 11 at lib/ref_tracker.c:179 ref_tracker_dir_exit (lib/ref_tracker.c:179)\nModules linked in:\nCPU: 1 UID: 0 PID: 11 Comm: kworker/u16:0 Not tainted 6.13.0-rc5-00147-g4c1224501e9d #5\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014\nWorkqueue: netns cleanup_net\nRIP: 0010:ref_tracker_dir_exit (lib/ref_tracker.c:179)\nCode: 00 00 00 fc ff df 4d 8b 26 49 bd 00 01 00 00 00 00 ad de 4c 39 f5 0f 85 df 00 00 00 48 8b 74 24 08 48 89 df e8 a5 cc 12 02 90 \u003c0f\u003e 0b 90 48 8d 6b 44 be 04 00 00 00 48 89 ef e8 80 de 67 ff 48 89\nRSP: 0018:ff11000007f3fb60 EFLAGS: 00010286\nRAX: 00000000000020ef RBX: ff1100000d6481e0 RCX: 1ffffffff0e40d82\nRDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8423ee3c\nRBP: ff1100000d648230 R08: 0000000000000001 R09: fffffbfff0e395af\nR10: 0000000000000001 R11: 0000000000000000 R12: ff1100000d648230\nR13: dead000000000100 R14: ff1100000d648230 R15: dffffc0000000000\nFS:  0000000000000000(0000) GS:ff1100006ce80000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00005620e1363990 CR3: 000000000eeb2002 CR4: 0000000000771ef0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400\nPKRU: 55555554\nCall Trace:\n \u003cTASK\u003e\n ? __warn (kernel/panic.c:748)\n ? ref_tracker_dir_exit (lib/ref_tracker.c:179)\n ? report_bug (lib/bug.c:201 lib/bug.c:219)\n ? handle_bug (arch/x86/kernel/traps.c:285)\n ? exc_invalid_op (arch/x86/kernel/traps.c:309 (discriminator 1))\n ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:621)\n ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/irqflags.h:42 ./arch/x86/include/asm/irqflags.h:97 ./arch/x86/include/asm/irqflags.h:155 ./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194)\n ? ref_tracker_dir_exit (lib/ref_tracker.c:179)\n ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:158)\n ? kfree (mm/slub.c:4613 mm/slub.c:4761)\n net_free (net/core/net_namespace.c:476 net/core/net_namespace.c:467)\n cleanup_net (net/cor\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 vulnerability is triggered exclusively through RTM_NEWLINK rtnetlink messages and netns creation/destruction from local syscalls; there is no remote packet path into pfcp_newlink().\nAC:L - The trigger is a fully deterministic four-command sequence (create two netns, create a pfcp link cross-netns, delete the socket\u0027s netns) with no race and no dependence on conditions outside the attacker\u0027s control; heap grooming of the freed net_cachep object is done simply by creating further namespaces.\nPR:L - CAP_NET_ADMIN over both netns is required, but an unprivileged user obtains it via `unshare -Urn` since both namespaces are owned by their own user namespace, satisfying netlink_net_capable() and rtnl_link_get_net_capable(); the pfcp module is auto-loaded via its rtnl-link alias.\nUI:N - The attacker performs the entire sequence itself through netlink and namespace syscalls; no victim action is involved.\nS:U - The corruption stays within the kernel\u0027s own security authority \u2014 a standard kernel memory-safety issue with no VM, IOMMU, or hypervisor boundary crossed.\nC:H - The dangling socket reads pointers (`net-\u003eipv4.udp_table`, `net-\u003ecore.prot_inuse`, `net_hash_mix()`) out of the freed and potentially reallocated `struct net`, giving a use-after-free read that can be leveraged to disclose kernel memory.\nI:H - udp_lib_unhash() and __netns_tracker_free() perform spinlock acquisition, list unlinking, and per-cpu increments on the freed netns object, yielding a write primitive at attacker-influenceable addresses once the slab slot is re-groomed with a new namespace.\nA:H - Deleting the socket\u0027s netns immediately produces a ref_tracker WARNING in cleanup_net (a panic under panic_on_warn) and permanently leaks the netdevice and socket, with the subsequent use-after-free reliably causing kernel corruption and crashes."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T11:53:33.356Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/1c35a66e2bfea53dea3562b2575ac7fd4c38ee61"
        },
        {
          "url": "https://git.kernel.org/stable/c/ffc90e9ca61b0f619326a1417ff32efd6cc71ed2"
        }
      ],
      "title": "pfcp: Destroy device along with udp socket\u0027s netns dismantle.",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-21677",
    "datePublished": "2025-01-31T11:25:38.809Z",
    "dateReserved": "2024-12-29T08:45:45.738Z",
    "dateUpdated": "2026-08-05T11:53:33.356Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Detection rules are retrieved from Rulezet.

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.

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.