CyberSecBulletin
CVE-2026-46280NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-46280 is a high-severity use after free 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 234071b4318feaeb27cd2e4e1b16ef6b055adf89, bf477abd448c76bb8ea51c9b4f63a3a17c4b6239, 5846715b6382dd4c6a69b35a56ca6115d33bc2a0 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 0.13% 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 234071b4318feaeb27cd2e4e1b16ef6b055adf89 or bf477abd448c76bb8ea51c9b4f63a3a17c4b6239 or 5846715b6382dd4c6a69b35a56ca6115d33bc2a0 or 38f113f81d3f0adc658a4475dd3ecaec985e21d3, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.1.176 or 6.6.140 or 6.12.86 or 6.18.27, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxb2ef9f5a5cb37643ca5def3516c546457074b882 up to, but not including, 234071b4318feaeb27cd2e4e1b16ef6b055adf89; b2ef9f5a5cb37643ca5def3516c546457074b882 up to, but not including, bf477abd448c76bb8ea51c9b4f63a3a17c4b6239; b2ef9f5a5cb37643ca5def3516c546457074b882 up to, but not including, 5846715b6382dd4c6a69b35a56ca6115d33bc2a0; b2ef9f5a5cb37643ca5def3516c546457074b882 up to, but not including, 38f113f81d3f0adc658a4475dd3ecaec985e21d3; b2ef9f5a5cb37643ca5def3516c546457074b882 up to, but not including, 9de1eb0aac2862d6144b8db0ec1388e79f8bc3e1; b2ef9f5a5cb37643ca5def3516c546457074b882 up to, but not including, 744dd97752ef1076a8d8672bb0d8aa2c7abc1144; 5.8234071b4318feaeb27cd2e4e1b16ef6b055adf89, bf477abd448c76bb8ea51c9b4f63a3a17c4b6239, 5846715b6382dd4c6a69b35a56ca6115d33bc2a0, 38f113f81d3f0adc658a4475dd3ecaec985e21d3, 9de1eb0aac2862d6144b8db0ec1388e79f8bc3e1, 744dd97752ef1076a8d8672bb0d8aa2c7abc1144
LinuxLinux Kernel5.8 up to, but not including, 6.1.176; 6.2 up to, but not including, 6.6.140; 6.7 up to, but not including, 6.12.86; 6.13 up to, but not including, 6.18.27; 6.19 up to, but not including, 7.0.46.1.176, 6.6.140, 6.12.86, 6.18.27, 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: lib: test_hmm: evict device pages on file close to avoid use-after-free Patch series "Minor hmm_test fixes and cleanups". Two bugfixes a cleanup for the HMM kernel selftests. These were mostly reported by Zenghui Yu with special thanks to Lorenzo for analysing and pointing out the problems. This patch (of 3): When dmirror_fops_release() is called it frees the dmirror struct but doesn't migrate device private pages back to system memory first. This leaves those pages with a dangling zone_device_data pointer to the freed dmirror. If a subsequent fault occurs on those pages (eg. during coredump) the dmirror_devmem_fault() callback dereferences the stale pointer causing a kernel panic. This was reported [1] when running mm/ksft_hmm.sh on arm64, where a test failure triggered SIGABRT and the resulting coredump walked the VMAs faulting in the stale device private pages. Fix this by calling dmirror_device_evict_chunk() for each devmem chunk in dmirror_fops_release() to migrate all device private pages back to system memory before freeing the dmirror struct. The function is moved earlier in the file to avoid a forward declaration.

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

The underlying weakness: Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

How developers prevent this class of flaw

  • Choose a language that provides automatic memory management.
  • When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

More Use After Free vulnerabilities (CWE-416)

Timeline

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

References

Recent Use After Free vulnerabilities

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