CyberSecBulletin
CVE-2026-31399NVD status: Analyzed

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-31399 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 6fc36c2a925ceaba203eb13d75a8f0879a2c121b, a36cf138500e56f50db9f9a33222df6969b38326, 9a0fb16ba5b372465a3a1ecd761c6fa911a4ab4d 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 0.12% 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 6fc36c2a925ceaba203eb13d75a8f0879a2c121b or a36cf138500e56f50db9f9a33222df6969b38326 or 9a0fb16ba5b372465a3a1ecd761c6fa911a4ab4d or e48bf8f1d2b12c1c5ba1f609edbd4cde5dadc20e, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.5 or 4.10 or 4.15 or 4.19, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxb6eae0f61db27748606cc00dafcfd1e2c032f0a5 up to, but not including, 6fc36c2a925ceaba203eb13d75a8f0879a2c121b; b6eae0f61db27748606cc00dafcfd1e2c032f0a5 up to, but not including, a36cf138500e56f50db9f9a33222df6969b38326; b6eae0f61db27748606cc00dafcfd1e2c032f0a5 up to, but not including, 9a0fb16ba5b372465a3a1ecd761c6fa911a4ab4d; b6eae0f61db27748606cc00dafcfd1e2c032f0a5 up to, but not including, e48bf8f1d2b12c1c5ba1f609edbd4cde5dadc20e; b6eae0f61db27748606cc00dafcfd1e2c032f0a5 up to, but not including, 2c638259ad750833fd46a0cf57672a618542d84c; b6eae0f61db27748606cc00dafcfd1e2c032f0a5 up to, but not including, a226e5b49e5fe8c98b14f8507de670189d191348; b6eae0f61db27748606cc00dafcfd1e2c032f0a5 up to, but not including, 84af19855d1abdee3c9d57c0684e2868e391793c; b6eae0f61db27748606cc00dafcfd1e2c032f0a5 up to, but not including, a8aec14230322ed8f1e8042b6d656c1631d41163; and 11 more ranges6fc36c2a925ceaba203eb13d75a8f0879a2c121b, a36cf138500e56f50db9f9a33222df6969b38326, 9a0fb16ba5b372465a3a1ecd761c6fa911a4ab4d, e48bf8f1d2b12c1c5ba1f609edbd4cde5dadc20e, 2c638259ad750833fd46a0cf57672a618542d84c, a226e5b49e5fe8c98b14f8507de670189d191348
LinuxLinux Kernel4.4.164 up to, but not including, 4.5; 4.9.137 up to, but not including, 4.10; 4.14.81 up to, but not including, 4.15; 4.18.19 up to, but not including, 4.19; 4.19.2 up to, but not including, 5.10.253; 5.11 up to, but not including, 5.15.203; 5.16 up to, but not including, 6.1.167; 6.2 up to, but not including, 6.6.130; and 4 more ranges4.5, 4.10, 4.15, 4.19, 5.10.253, 5.15.203

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 NVD.

Official description

In the Linux kernel, the following vulnerability has been resolved: nvdimm/bus: Fix potential use after free in asynchronous initialization Dingisoul with KASAN reports a use after free if device_add() fails in nd_async_device_register(). Commit b6eae0f61db2 ("libnvdimm: Hold reference on parent while scheduling async init") correctly added a reference on the parent device to be held until asynchronous initialization was complete. However, if device_add() results in an allocation failure the ref count of the device drops to 0 prior to the parent pointer being accessed. Thus resulting in use after free. The bug bot AI correctly identified the fix. Save a reference to the parent pointer to be used to drop the parent reference regardless of the outcome of device_add().

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: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Use After Free vulnerabilities

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