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CVE-2026-46081NVD status: Undergoing Analysis

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2026-46081 is a high-severity out-of-bounds write vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 343a5bf68a8ff9affcf2b70677ea4cf40c195ee4, 1a2785e5985627f2265ba7775949601a29ba0d1e, d7e20b9bd6c990773cf0c09e2642250b8a70263d as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.17% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 343a5bf68a8ff9affcf2b70677ea4cf40c195ee4 or 1a2785e5985627f2265ba7775949601a29ba0d1e or d7e20b9bd6c990773cf0c09e2642250b8a70263d, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.18.27 or 7.0.4, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux64929fe8c0a43508eee952cf57903a61c52601e7 up to, but not including, 343a5bf68a8ff9affcf2b70677ea4cf40c195ee4; 64929fe8c0a43508eee952cf57903a61c52601e7 up to, but not including, 1a2785e5985627f2265ba7775949601a29ba0d1e; 64929fe8c0a43508eee952cf57903a61c52601e7 up to, but not including, d7e20b9bd6c990773cf0c09e2642250b8a70263d; 6.16343a5bf68a8ff9affcf2b70677ea4cf40c195ee4, 1a2785e5985627f2265ba7775949601a29ba0d1e, d7e20b9bd6c990773cf0c09e2642250b8a70263d
LinuxLinux Kernel6.16 up to, but not including, 6.18.27; 6.19 up to, but not including, 7.0.46.18.27, 7.0.4

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: crypto: acomp - fix wrong pointer stored by acomp_save_req() acomp_save_req() stores &req->chain in req->base.data. When acomp_reqchain_done() is invoked on asynchronous completion, it receives &req->chain as the data argument but casts it directly to struct acomp_req. Since data points to the chain member, all subsequent field accesses are at a wrong offset, resulting in memory corruption. The issue occurs when an asynchronous hardware implementation, such as the QAT driver, completes a request that uses the DMA virtual address interface (e.g. acomp_request_set_src_dma()). This combination causes crypto_acomp_compress() to enter the acomp_do_req_chain() path, which sets acomp_reqchain_done() as the completion callback via acomp_save_req(). With KASAN enabled, this manifests as a general protection fault in acomp_reqchain_done(): general protection fault, probably for non-canonical address 0xe000040000000000 KASAN: probably user-memory-access in range [0x0000400000000000-0x0000400000000007] RIP: 0010:acomp_reqchain_done+0x15b/0x4e0 Call Trace: <IRQ> qat_comp_alg_callback+0x5d/0xa0 [intel_qat] adf_ring_response_handler+0x376/0x8b0 [intel_qat] adf_response_handler+0x60/0x170 [intel_qat] tasklet_action_common+0x223/0x820 handle_softirqs+0x1ab/0x640 </IRQ> Fix this by storing the request itself in req->base.data instead of &req->chain, so that acomp_reqchain_done() receives the correct pointer. Simplify acomp_restore_req() accordingly to access req->chain directly.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Out-of-bounds Write vulnerabilities (CWE-787)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Write vulnerabilities

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