CyberSecBulletin
CVE-2025-37885NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2025-37885 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 e5f2dee9f7fcd2ff4b97869f3c66a0d89c167769, 116c7d35b8f72eac383b9fd371d7c1a8ffc2968b, 023816bd5fa46fab94d1e7917fe131b79ed1fb41 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 0.32% 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 e5f2dee9f7fcd2ff4b97869f3c66a0d89c167769 or 116c7d35b8f72eac383b9fd371d7c1a8ffc2968b or 023816bd5fa46fab94d1e7917fe131b79ed1fb41 or 3481fd96d801715942b6f69fe251133128156f30, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.237 or 5.15.181 or 6.1.136 or 6.6.89, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxefc644048ecde54f016011fe10110addd0de348f up to, but not including, e5f2dee9f7fcd2ff4b97869f3c66a0d89c167769; efc644048ecde54f016011fe10110addd0de348f up to, but not including, 116c7d35b8f72eac383b9fd371d7c1a8ffc2968b; efc644048ecde54f016011fe10110addd0de348f up to, but not including, 023816bd5fa46fab94d1e7917fe131b79ed1fb41; efc644048ecde54f016011fe10110addd0de348f up to, but not including, 3481fd96d801715942b6f69fe251133128156f30; efc644048ecde54f016011fe10110addd0de348f up to, but not including, b5de7ac74f69603ad803c524b840bffd36368fc3; efc644048ecde54f016011fe10110addd0de348f up to, but not including, 3066ec21d1a33896125747f68638725f456308db; efc644048ecde54f016011fe10110addd0de348f up to, but not including, 9bcac97dc42d2f4da8229d18feb0fe2b1ce523a2; 4.4e5f2dee9f7fcd2ff4b97869f3c66a0d89c167769, 116c7d35b8f72eac383b9fd371d7c1a8ffc2968b, 023816bd5fa46fab94d1e7917fe131b79ed1fb41, 3481fd96d801715942b6f69fe251133128156f30, b5de7ac74f69603ad803c524b840bffd36368fc3, 3066ec21d1a33896125747f68638725f456308db
LinuxLinux Kernel4.4 up to, but not including, 5.10.237; 5.11 up to, but not including, 5.15.181; 5.16 up to, but not including, 6.1.136; 6.2 up to, but not including, 6.6.89; 6.7 up to, but not including, 6.12.26; 6.13 up to, but not including, 6.14.5; 6.155.10.237, 5.15.181, 6.1.136, 6.6.89, 6.12.26, 6.14.5
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: KVM: x86: Reset IRTE to host control if *new* route isn't postable Restore an IRTE back to host control (remapped or posted MSI mode) if the *new* GSI route prevents posting the IRQ directly to a vCPU, regardless of the GSI routing type. Updating the IRTE if and only if the new GSI is an MSI results in KVM leaving an IRTE posting to a vCPU. The dangling IRTE can result in interrupts being incorrectly delivered to the guest, and in the worst case scenario can result in use-after-free, e.g. if the VM is torn down, but the underlying host IRQ isn't freed.

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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