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VulnerabilityPublished Updated

CVE-2025-37823: Linux kernel · net_sched: hfsc: Fix a potential UAF in hfsc_dequeue() too

Affects Linux kernelSource GCVE Database

0

Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1088.95~20.04.1 : patch Linux kernel soon.

Data as of 28 Oct 2026, 11:31 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 5.15.0-1088.95~20.04.1, 5.15.0-1094.103~20.04.1, 5.15.0-1087.96~20.04.2 +60
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 8 May 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threatsAffected
  • 6.17.0-1003.3 – 6.17.0-1017.17
10 affected builds
Fixed in–
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-100.100
Fixed in
  • 6.8.0-100.100
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1046.49
Fixed in
  • 6.8.0-1046.49
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1046.52
Fixed in
  • 6.8.0-1046.52
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threatsAffected
  • 6.11.0-1008.8~24.04.1 – 6.11.0-1018.18~24.04.1
7 affected builds
Fixed in–
Ubuntu 24.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1046.53
Fixed in
  • 6.8.0-1046.53

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Official patches are available and should be applied to affected Linux kernel versions as listed in the vendor advisory. Systems running affected versions should be updated to the fixed kernel releases to remediate this vulnerability. No additional mitigation actions are indicated by the vendor advisory.

Description

CVE-2025-37823 is a use-after-free (UAF) vulnerability in the Linux kernel's net_sched subsystem, specifically in the hfsc_dequeue() function. The issue was addressed by adding safeguards to hfsc_dequeue(), similar to a previous patch. There is no reliable reproducer for this vulnerability. Multiple Linux kernel versions prior to certain 5.15.x releases and several older 3.x versions are affected. The vulnerability has been fixed in various 5.15.x kernel releases. The flaw has a high severity with a CVSS score of 7.8, indicating potential for significant impact if exploited. No known exploits are reported in the wild. The vendor has released official patches to remediate the issue.

References

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