VulnerabilityPublished 4 Sep 2026Updated 30 Oct 2026

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

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in fadbc1ed2a872a8649a44cf9e1cf9621fc58cd6e : patch Linux kernel soon.

Data as of 30 Oct 2026, 13:17 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none

Patch: Available – fixed in fadbc1ed2a872a8649a44cf9e1cf9621fc58cd6e, cd7e875b89597f3498917af764758391338d1802, bc09411a11b5a676c59ff8612c6873d014f6fb36 +6

Exploitation evidence

Disclosed: evidence found.
CVE published 4 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ e8f69799810c32dd40c6724d829eccc70baad07f, < fadbc1ed2a872a8649a44cf9e1cf9621fc58cd6e	Fixed in fadbc1ed2a872a8649a44cf9e1cf9621fc58cd6e
LinuxLinux	Affected ≥ e8f69799810c32dd40c6724d829eccc70baad07f, < cd7e875b89597f3498917af764758391338d1802	Fixed in cd7e875b89597f3498917af764758391338d1802
LinuxLinux	Affected ≥ e8f69799810c32dd40c6724d829eccc70baad07f, < bc09411a11b5a676c59ff8612c6873d014f6fb36	Fixed in bc09411a11b5a676c59ff8612c6873d014f6fb36
LinuxLinux	Affected ≥ e8f69799810c32dd40c6724d829eccc70baad07f, < b17cf742eaad70ae29ac558cefb3aa9bbeea03d4	Fixed in b17cf742eaad70ae29ac558cefb3aa9bbeea03d4
LinuxLinux	Affected ≥ e8f69799810c32dd40c6724d829eccc70baad07f, < b7f10d4ff987bda038df90052cd4a1434a7412d4	Fixed in b7f10d4ff987bda038df90052cd4a1434a7412d4
LinuxLinux	Affected ≥ e8f69799810c32dd40c6724d829eccc70baad07f, < a832d7cb09da2a8e4e9734b4be14d3e76169d805	Fixed in a832d7cb09da2a8e4e9734b4be14d3e76169d805

AI-suggested

A fix for this vulnerability has been committed in multiple Linux kernel versions as indicated by the fixed commit hashes. Users should update their Linux kernel to a version including these fixes to remediate the issue. No additional mitigations are required once the kernel is updated.

Description

CVE-2026-80852 is a vulnerability in the Linux kernel's TLS device code that causes an out-of-bounds write in the tls_append_frag() function. This flaw arises due to improper bounds checking on fragment counts during TLS record assembly when using TLS offload with certain NICs. The issue can lead to memory corruption and kernel crashes triggered by the workqueue processing corrupted data structures.

Impact

The vulnerability allows an attacker with local access to trigger out-of-bounds writes in kernel memory, leading to memory corruption, kernel crashes (KASAN detected), and potential execution of unauthorized code in kernel mode. This compromises kernel stability and security on affected systems with TLS offload capable NICs. No public exploits or in-the-wild exploitation are known at this time.

Summary

This vulnerability affects the Linux kernel's TLS offload device implementation, specifically in tls_append_frag(). The tls_push_data() function fails to properly check fragment counts when MSG_MORE is used, allowing tls_append_frag() to write beyond the bounds of the frags array. This results in out-of-bounds writes to kernel memory, corrupting adjacent structures such as destruct_work. The flaw was discovered via syzkaller and syzbot testing on netdevsim TLS offload emulation. Kernel Address Sanitizer (KASAN) and Undefined Behavior Sanitizer (UBSAN) reports confirm slab out-of-bounds and array index out-of-bounds errors. The issue can cause kernel panics and potential execution of NX-protected pages, indicating a serious memory safety violation. The vulnerability is reachable only on machines with NICs implementing TLS offload.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 30 Oct 2026, 13:17 UTC

Technical details

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