CyberSecBulletin
CVE-2026-68293NVD status: Received

Linux: Heap-based Buffer Overflow

Published Updated By the CyberSecBulletin desk

CVE-2026-68293 is a high-severity heap-based buffer overflow vulnerability in Linux, with a CVSS 3.1 base score of 7.1 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 5ed6d41029832b11bc204d7cc326cf309d073666, c8a4acc19dcdc83e1303c29d9535e5c99415a2e3, 5be4eebd5a3a198dab0adcd550e1cadca79bdfed 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 5ed6d41029832b11bc204d7cc326cf309d073666 or c8a4acc19dcdc83e1303c29d9535e5c99415a2e3 or 5be4eebd5a3a198dab0adcd550e1cadca79bdfed or 87b39a8c875ca744b7de69af0a8ef8874cffccf1, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux271907ee2f29cd1078fd219f0778fd824fb1971c up to, but not including, 5ed6d41029832b11bc204d7cc326cf309d073666; 271907ee2f29cd1078fd219f0778fd824fb1971c up to, but not including, c8a4acc19dcdc83e1303c29d9535e5c99415a2e3; 271907ee2f29cd1078fd219f0778fd824fb1971c up to, but not including, 5be4eebd5a3a198dab0adcd550e1cadca79bdfed; 271907ee2f29cd1078fd219f0778fd824fb1971c up to, but not including, 87b39a8c875ca744b7de69af0a8ef8874cffccf1; 271907ee2f29cd1078fd219f0778fd824fb1971c up to, but not including, 88b2a16ddac3357e3f1d528e758b51e2c945d546; 271907ee2f29cd1078fd219f0778fd824fb1971c up to, but not including, 11c057d23465c7a5817a7284c896d19d54c0b616; 5.185ed6d41029832b11bc204d7cc326cf309d073666, c8a4acc19dcdc83e1303c29d9535e5c99415a2e3, 5be4eebd5a3a198dab0adcd550e1cadca79bdfed, 87b39a8c875ca744b7de69af0a8ef8874cffccf1, 88b2a16ddac3357e3f1d528e758b51e2c945d546, 11c057d23465c7a5817a7284c896d19d54c0b616

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
NoneNothing can be modified.
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:N/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Fix MCIA register buffer overflow on 32 dword reads The MCIA register can return up to 32 dwords (128 bytes) when the device advertises the mcia_32dwords capability, but struct mlx5_ifc_mcia_reg_bits only defines dword_0..11, leaving room for just 12 dwords (48 bytes) of data. mlx5_query_mcia() clamps the read size to mlx5_mcia_max_bytes() and then memcpy()s that many bytes out of the register, potentially reading past the end of the 'out' buffer. On kernels built with FORTIFY_SOURCE this is caught as a buffer overflow while reading the module EEPROM via ethtool: detected buffer overflow in memcpy kernel BUG at lib/string_helpers.c:1048! RIP: 0010:fortify_panic+0x13/0x20 Call Trace: mlx5_query_mcia.isra.0+0x200/0x210 [mlx5_core] mlx5_query_module_eeprom_by_page+0x4a/0xa0 [mlx5_core] mlx5e_get_module_eeprom_by_page+0xbb/0x120 [mlx5_core] eeprom_prepare_data+0xf3/0x170 ethnl_default_doit+0xf1/0x3b0 Extend the mcia_reg layout to 32 dwords.

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

The underlying weakness: Heap-based Buffer Overflow

The product writes past the end of a buffer that was allocated on the heap.

How developers prevent this class of flaw

  • Pre-design: Use a language or compiler that performs automatic bounds checking.
  • Use an abstraction library to abstract away risky APIs. Not a complete solution.
  • 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 Heap-based Buffer Overflow vulnerabilities (CWE-122)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Heap-based Buffer Overflow vulnerabilities

Spotted an error? Tell us.