CVE-2025-21812: Linux kernel · ax25: rcu protect dev->ax25_ptr
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 6.8.0-1032.34~22.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 16% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1032.34~22.04.1, 6.8.0-1034.39~22.04.1, 6.8.0-1033.35~22.04.1 +30
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 27 Feb 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux@6.8.0-64.67?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws@6.8.0-1032.34?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure@6.8.0-1034.39?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11@6.11.0-1015.15~24.04.1?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-nvidiapkg:deb/ubuntu/linux-azure-nvidia@6.8.0-1022.23?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp@6.8.0-1033.35?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available and should be applied to affected linux-aws kernel versions. The vendor advisory from Ubuntu confirms that this issue is fixed in updated kernel releases. Users should update to the fixed kernel versions as soon as possible to mitigate the risk. No additional mitigation steps are required beyond applying the official kernel updates.
Description
A locking dependency vulnerability in the Linux kernel's ax25 network subsystem has been resolved. The issue involved a circular locking dependency between rtnl_mutex and sk_lock-AF_AX25 in the ax25_setsockopt() function, which could lead to deadlocks and potential use-after-free conditions. This flaw was identified by syzbot and affects specific linux-aws kernel versions. The vulnerability has been fixed in updated kernel releases as part of a broader security update addressing multiple kernel subsystems.
References
- ubuntu.com/security/CVE-2025-21812 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-21812 (opens in a new tab)
- git.kernel.org/linus/95fc45d1dea8e1253f8ec58abc5befb71553d666 (opens in a new tab)
- git.kernel.org/stable/c/2802ed4ced27ebd474828fc67ffd7d66f11e3605 (opens in a new tab)
- git.kernel.org/stable/c/7705d8a7f2c26c80973c81093db07c6022b2b30e (opens in a new tab)
- git.kernel.org/stable/c/8937f5e38a218531dce2a89fae60e3adcc2311e1 (opens in a new tab)
- git.kernel.org/stable/c/95fc45d1dea8e1253f8ec58abc5befb71553d666 (opens in a new tab)
- git.kernel.org/stable/c/c2531db6de3c95551be58878f859c6a053b7eb2e (opens in a new tab)
- ubuntu.com/security/notices/USN-7521-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7521-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7521-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7652-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7653-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-6 (opens in a new tab)
- ubuntu.com/security/notices/USN-7737-1 (opens in a new tab)