CVE-2026-80852tls: device: fix out-of-bounds write in tls_append_frag()

Description

In 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: <TASK> 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) </TASK> 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: <TASK> 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) </TASK>

Timeline

Scores

No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.

EPSS (exploitation in 30 days)

0.18% · top 92% of all CVEs (15 Nov 2026)

The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.

Affected products

• Linux · Linux

  • affected e8f69799810c32dd40c6724d829eccc70baad07f – < bc09411a11b5a676c59ff8612c6873d014f6fb36
  • affected e8f69799810c32dd40c6724d829eccc70baad07f – < 1fc6eb0c756b8be693b72e9e636ae5e236dcb6ee
  • affected e8f69799810c32dd40c6724d829eccc70baad07f – < 03ced5da6120965d80ed56dbb7d78fa5c9128906
  • affected e8f69799810c32dd40c6724d829eccc70baad07f – < a832d7cb09da2a8e4e9734b4be14d3e76169d805
  • affected e8f69799810c32dd40c6724d829eccc70baad07f – < b7f10d4ff987bda038df90052cd4a1434a7412d4
  • affected e8f69799810c32dd40c6724d829eccc70baad07f – < fadbc1ed2a872a8649a44cf9e1cf9621fc58cd6e
  • affected e8f69799810c32dd40c6724d829eccc70baad07f – < cd7e875b89597f3498917af764758391338d1802
  • affected e8f69799810c32dd40c6724d829eccc70baad07f – < 7e1208c135618358da5d7d6664874dc6e53c62fc
  • affected e8f69799810c32dd40c6724d829eccc70baad07f – < b17cf742eaad70ae29ac558cefb3aa9bbeea03d4

• Linux · Linux

  • affected 4.18
  • unaffected < 4.18
  • unaffected 5.10.273 – ≤ 5.10.*
  • unaffected 5.15.224 – ≤ 5.15.*
  • unaffected 6.1.187 – ≤ 6.1.*
  • unaffected 6.6.156 – ≤ 6.6.*
  • unaffected 6.12.108 – ≤ 6.12.*
  • unaffected 6.18.49 – ≤ 6.18.*
  • unaffected 7.1.13 – ≤ 7.1.*
  • unaffected 7.2.3 – ≤ 7.2.*
  • unaffected 7.3 – ≤ *

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-71302 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

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Record last updated 30 Oct 2026, 12:31 UTC.