CyberSecBulletin
CVE-2025-38377NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2025-38377 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 94e0918e39039c47ddceb609500817f7266be756, fe62a35fb1f77f494ed534fc69a9043dc5a30ce1, 2b952dbb32fef835756f07ff0cd77efbb836dfea 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 0.28% 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 94e0918e39039c47ddceb609500817f7266be756 or fe62a35fb1f77f494ed534fc69a9043dc5a30ce1 or 2b952dbb32fef835756f07ff0cd77efbb836dfea or b6b232e16e08c6dc120672b4753392df0d28c1b4, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.4.296 or 5.10.240 or 5.15.187 or 6.1.144, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 94e0918e39039c47ddceb609500817f7266be756; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, fe62a35fb1f77f494ed534fc69a9043dc5a30ce1; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 2b952dbb32fef835756f07ff0cd77efbb836dfea; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, b6b232e16e08c6dc120672b4753392df0d28c1b4; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 7a1841c9609377e989ec41c16551309ce79c39e4; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 446ac00b86be1670838e513b643933d78837d8db; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 2c6c82ee074bfcfd1bc978ec45bfea37703d840a; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 34a500caf48c47d5171f4aa1f237da39b07c6157; and 1 more ranges94e0918e39039c47ddceb609500817f7266be756, fe62a35fb1f77f494ed534fc69a9043dc5a30ce1, 2b952dbb32fef835756f07ff0cd77efbb836dfea, b6b232e16e08c6dc120672b4753392df0d28c1b4, 7a1841c9609377e989ec41c16551309ce79c39e4, 446ac00b86be1670838e513b643933d78837d8db
LinuxLinux Kernel2.6.13 up to, but not including, 5.4.296; 5.5 up to, but not including, 5.10.240; 5.11 up to, but not including, 5.15.187; 5.16 up to, but not including, 6.1.144; 6.2 up to, but not including, 6.6.97; 6.7 up to, but not including, 6.12.37; 6.13 up to, but not including, 6.15.6; 2.6.12; and 1 more ranges5.4.296, 5.10.240, 5.15.187, 6.1.144, 6.6.97, 6.12.37
DebianDebian Linux11.0Not stated

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.

Scoring systemScoreSeverityScored by
CVSS 3.18.8HighCNA
CVSS 3.17.8HighNVD

Official description

In the Linux kernel, the following vulnerability has been resolved: rose: fix dangling neighbour pointers in rose_rt_device_down() There are two bugs in rose_rt_device_down() that can cause use-after-free: 1. The loop bound `t->count` is modified within the loop, which can cause the loop to terminate early and miss some entries. 2. When removing an entry from the neighbour array, the subsequent entries are moved up to fill the gap, but the loop index `i` is still incremented, causing the next entry to be skipped. For example, if a node has three neighbours (A, A, B) with count=3 and A is being removed, the second A is not checked. i=0: (A, A, B) -> (A, B) with count=2 ^ checked i=1: (A, B) -> (A, B) with count=2 ^ checked (B, not A!) i=2: (doesn't occur because i < count is false) This leaves the second A in the array with count=2, but the rose_neigh structure has been freed. Code that accesses these entries assumes that the first `count` entries are valid pointers, causing a use-after-free when it accesses the dangling pointer. Fix both issues by iterating over the array in reverse order with a fixed loop bound. This ensures that all entries are examined and that the removal of an entry doesn't affect subsequent iterations.

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

References

Third-party and government advisories

Recent Use After Free vulnerabilities

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