CyberSecBulletin
CVE-2025-38724NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2025-38724 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 3f252a73e81aa01660cb426735eab932e6182e8d, d35ac850410966010e92f401f4e21868a9ea4d8b, f3aac6cf390d8b80e1d82975faf4ac61175519c0 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 0.41% 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 3f252a73e81aa01660cb426735eab932e6182e8d or d35ac850410966010e92f401f4e21868a9ea4d8b or f3aac6cf390d8b80e1d82975faf4ac61175519c0 or 22f45cedf281e6171817c8a3432c44d788c550e1, whichever matches your release line, or a later version.
  2. Update SIMATIC CN 4100 to V5.0 or a later version.
  3. Update Linux Kernel to 5.4.297 or 5.10.241 or 5.15.190 or 6.1.149, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxd20c11d86d8f821a64eac7d6c8f296f06d935f4f up to, but not including, 3f252a73e81aa01660cb426735eab932e6182e8d; d20c11d86d8f821a64eac7d6c8f296f06d935f4f up to, but not including, d35ac850410966010e92f401f4e21868a9ea4d8b; d20c11d86d8f821a64eac7d6c8f296f06d935f4f up to, but not including, f3aac6cf390d8b80e1d82975faf4ac61175519c0; d20c11d86d8f821a64eac7d6c8f296f06d935f4f up to, but not including, 22f45cedf281e6171817c8a3432c44d788c550e1; d20c11d86d8f821a64eac7d6c8f296f06d935f4f up to, but not including, d71abd1ae4e0413707cd42b10c24a11d1aa71772; d20c11d86d8f821a64eac7d6c8f296f06d935f4f up to, but not including, 74ad36ed60df561a303a19ecef400c7096b20306; d20c11d86d8f821a64eac7d6c8f296f06d935f4f up to, but not including, 36e83eda90e0e4ac52f259f775b40b2841f8a0a3; d20c11d86d8f821a64eac7d6c8f296f06d935f4f up to, but not including, 571a5e46c71490285d2d8c06f6b5a7cbf6c7edd1; and 2 more ranges3f252a73e81aa01660cb426735eab932e6182e8d, d35ac850410966010e92f401f4e21868a9ea4d8b, f3aac6cf390d8b80e1d82975faf4ac61175519c0, 22f45cedf281e6171817c8a3432c44d788c550e1, d71abd1ae4e0413707cd42b10c24a11d1aa71772, 74ad36ed60df561a303a19ecef400c7096b20306
SiemensSIMATIC CN 4100before V5.0V5.0
SiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFPV3.1.5 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFPV3.1.5 and laterNot stated
SiemensSIPLUS S7-1500 CPU 1518-4 PN/DP MFPV3.1.5 and laterNot stated
LinuxLinux Kernel3.17 up to, but not including, 5.4.297; 5.5 up to, but not including, 5.10.241; 5.11 up to, but not including, 5.15.190; 5.16 up to, but not including, 6.1.149; 6.2 up to, but not including, 6.6.103; 6.7 up to, but not including, 6.12.43; 6.13 up to, but not including, 6.15.11; 6.16 up to, but not including, 6.16.25.4.297, 5.10.241, 5.15.190, 6.1.149, 6.6.103, 6.12.43
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 3.19.8CriticalCNA
CVSS 3.17.8HighNVD

Official description

In the Linux kernel, the following vulnerability has been resolved: nfsd: handle get_client_locked() failure in nfsd4_setclientid_confirm() Lei Lu recently reported that nfsd4_setclientid_confirm() did not check the return value from get_client_locked(). a SETCLIENTID_CONFIRM could race with a confirmed client expiring and fail to get a reference. That could later lead to a UAF. Fix this by getting a reference early in the case where there is an extant confirmed client. If that fails then treat it as if there were no confirmed client found at all. In the case where the unconfirmed client is expiring, just fail and return the result from get_client_locked().

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

Third-party and government advisories

Recent Use After Free vulnerabilities

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