GHSA-3586-6WJW-9G84
Vulnerability from github – Published: 2026-09-04 18:31 – Updated: 2026-09-04 18:31In the Linux kernel, the following vulnerability has been resolved:
tls: device: fix out-of-bounds write in tls_append_frag()
Found with syzkaller and a local syzbot instance running on top of a netdevsim TLS offload emulation; tls_device.c is otherwise only reachable on a machine with a NIC that implements the offload.
tls_push_data() only checks whether the open record still has room for another frag at the bottom of its loop, and the MSG_MORE early break skips that check. The record survives to the next syscall with the frag count it already had, and tls_append_frag() does not check either, so with TLS_TX_ZEROCOPY_RO every splice(SPLICE_F_MORE) of a byte or two adds a non-coalescing pipe page and num_frags walks off the end of tls_record_info.frags[MAX_SKB_FRAGS]. Once the record is pushed, tls_push_record() runs the same index over sg_tx_data[MAX_SKB_FRAGS] and the sg_set_page() writes land on the destruct_work that follows it, which the workqueue then calls.
The byte limit is fine because copy drops to 0 and the loop falls through to the same check; the frag count has no such feedback.
Push the record rather than keep a full one open, which is what a plain TCP socket does - tcp_sendmsg_locked() uses tcp_mark_push() and new_segment in both the copy and the MSG_SPLICE_PAGES paths, and tls_sw already sets full_record when the sk_msg ring fills up, MSG_MORE or not.
BUG: KASAN: slab-out-of-bounds in tls_append_frag ( net/tls/tls_device.c:269) Write of size 8 at addr ffff8881104d1530 by task tls_oob/450
CPU: 2 UID: 0 PID: 450 Comm: tls_oob Not tainted 7.2.0-rc7+ #329 PREEMPT Call Trace: dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120) print_report (mm/kasan/report.c:378 mm/kasan/report.c:482) kasan_report (mm/kasan/report.c:595) tls_append_frag (net/tls/tls_device.c:269) tls_push_data (net/tls/tls_device.c:518) tls_device_sendmsg (net/tls/tls_device.c:583) inet_sendmsg (net/ipv4/af_inet.c:865) sock_sendmsg (net/socket.c:775 net/socket.c:790 net/socket.c:813) splice_to_socket (fs/splice.c:884) do_splice (fs/splice.c:936 fs/splice.c:1349) __do_splice (fs/splice.c:1431) __x64_sys_splice (fs/splice.c:1634 fs/splice.c:1616) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
and, once the record is pushed:
UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:300:24 index 18 is out of range for type 'skb_frag_t [17]' UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:301:41 index 18 is out of range for type 'scatterlist [17]' UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:302:39 index 18 is out of range for type 'scatterlist [17]' UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:307:38 index 26 is out of range for type 'scatterlist [17]'
kernel tried to execute NX-protected page - exploit attempt? (uid: 0) BUG: unable to handle page fault for address: ffffea000411a680 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0011) - permissions violation Oops: Oops: 0011 [#1] SMP KASAN PTI Workqueue: ktls_device_destruct 0xffffea000411a680 RIP: 0010:0xffffea000411a680 Call Trace: worker_thread (kernel/workqueue.c:3405 kernel/workqueue.c:3486) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245)
{
"affected": [],
"aliases": [
"CVE-2026-80852"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-04T16:18:14Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntls: device: fix out-of-bounds write in tls_append_frag()\n\nFound with syzkaller and a local syzbot instance running on top of a\nnetdevsim TLS offload emulation; tls_device.c is otherwise only reachable\non a machine with a NIC that implements the offload.\n\ntls_push_data() only checks whether the open record still has room for\nanother frag at the bottom of its loop, and the MSG_MORE early break\nskips that check. The record survives to the next syscall with the frag\ncount it already had, and tls_append_frag() does not check either, so\nwith TLS_TX_ZEROCOPY_RO every splice(SPLICE_F_MORE) of a byte or two adds\na non-coalescing pipe page and num_frags walks off the end of\ntls_record_info.frags[MAX_SKB_FRAGS]. Once the record is pushed,\ntls_push_record() runs the same index over sg_tx_data[MAX_SKB_FRAGS] and\nthe sg_set_page() writes land on the destruct_work that follows it, which\nthe workqueue then calls.\n\nThe byte limit is fine because copy drops to 0 and the loop falls through\nto the same check; the frag count has no such feedback.\n\nPush the record rather than keep a full one open, which is what a plain\nTCP socket does - tcp_sendmsg_locked() uses tcp_mark_push() and\nnew_segment in both the copy and the MSG_SPLICE_PAGES paths, and tls_sw\nalready sets full_record when the sk_msg ring fills up, MSG_MORE or not.\n\n BUG: KASAN: slab-out-of-bounds in tls_append_frag ( net/tls/tls_device.c:269)\n Write of size 8 at addr ffff8881104d1530 by task tls_oob/450\n\n CPU: 2 UID: 0 PID: 450 Comm: tls_oob Not tainted 7.2.0-rc7+ #329 PREEMPT\n Call Trace:\n \u003cTASK\u003e\n dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120)\n print_report (mm/kasan/report.c:378 mm/kasan/report.c:482)\n kasan_report (mm/kasan/report.c:595)\n tls_append_frag (net/tls/tls_device.c:269)\n tls_push_data (net/tls/tls_device.c:518)\n tls_device_sendmsg (net/tls/tls_device.c:583)\n inet_sendmsg (net/ipv4/af_inet.c:865)\n sock_sendmsg (net/socket.c:775 net/socket.c:790 net/socket.c:813)\n splice_to_socket (fs/splice.c:884)\n do_splice (fs/splice.c:936 fs/splice.c:1349)\n __do_splice (fs/splice.c:1431)\n __x64_sys_splice (fs/splice.c:1634 fs/splice.c:1616)\n do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n \u003c/TASK\u003e\n\nand, once the record is pushed:\n\n UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:300:24\n index 18 is out of range for type \u0027skb_frag_t [17]\u0027\n UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:301:41\n index 18 is out of range for type \u0027scatterlist [17]\u0027\n UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:302:39\n index 18 is out of range for type \u0027scatterlist [17]\u0027\n UBSAN: array-index-out-of-bounds in net/tls/tls_device.c:307:38\n index 26 is out of range for type \u0027scatterlist [17]\u0027\n\n kernel tried to execute NX-protected page - exploit attempt? (uid: 0)\n BUG: unable to handle page fault for address: ffffea000411a680\n #PF: supervisor instruction fetch in kernel mode\n #PF: error_code(0x0011) - permissions violation\n Oops: Oops: 0011 [#1] SMP KASAN PTI\n Workqueue: ktls_device_destruct 0xffffea000411a680\n RIP: 0010:0xffffea000411a680\n Call Trace:\n \u003cTASK\u003e\n worker_thread (kernel/workqueue.c:3405 kernel/workqueue.c:3486)\n kthread (kernel/kthread.c:436)\n ret_from_fork (arch/x86/kernel/process.c:158)\n ret_from_fork_asm (arch/x86/entry/entry_64.S:245)\n \u003c/TASK\u003e",
"id": "GHSA-3586-6wjw-9g84",
"modified": "2026-09-04T18:31:29Z",
"published": "2026-09-04T18:31:29Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80852"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/03ced5da6120965d80ed56dbb7d78fa5c9128906"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7e1208c135618358da5d7d6664874dc6e53c62fc"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a832d7cb09da2a8e4e9734b4be14d3e76169d805"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b17cf742eaad70ae29ac558cefb3aa9bbeea03d4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b7f10d4ff987bda038df90052cd4a1434a7412d4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/cd7e875b89597f3498917af764758391338d1802"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fadbc1ed2a872a8649a44cf9e1cf9621fc58cd6e"
}
],
"schema_version": "1.4.0",
"severity": []
}
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