CVE-2025-21884: Linux kernel · net: better track kernel sockets lifetime
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 6.8.0-1046.49~22.04.1 : patch Linux kernel soon.
Data as of 30 Oct 2026, 23:12 UTC
- Patch
- Available – fixed in 6.8.0-1046.49~22.04.1, 6.8.0-1051.57~22.04.1, 6.8.0-1046.53~22.04.1 +27
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 Mar 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- ubuntu.com/security/notices/USN-8028-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8031-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8031-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-6 (opens in a new tab)
- ubuntu.com/security/notices/USN-8031-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8052-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-7 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-8 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-nvidiapkg:deb/ubuntu/linux-azure-nvidia?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 included in Linux kernel versions 6.8.0-1046.49 and later. Users should update to these fixed versions to remediate the vulnerability. No additional mitigation actions are indicated by the vendor advisory.
Description
CVE-2025-21884 is a vulnerability in the Linux kernel related to improper tracking of kernel socket lifetimes. Kernel sockets may be freed prematurely due to delayed freeing caused by packets still held in queues, leading to reference count warnings and potential stability issues. The flaw has been fixed by ensuring kernel sockets maintain proper references and by introducing a helper function for reference counting. The vulnerability affects multiple Linux kernel versions prior to 6.8.0-1046.49 and similar builds. A patch is available and has been incorporated in fixed kernel releases.
References
- ubuntu.com/security/CVE-2025-21884 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-21884 (opens in a new tab)
- git.kernel.org/linus/5c70eb5c593d64d93b178905da215a9fd288a4b5 (opens in a new tab)
- git.kernel.org/stable/c/5c70eb5c593d64d93b178905da215a9fd288a4b5 (opens in a new tab)
- git.kernel.org/stable/c/c31a732fac46b00b95b78fcc9c37cb48dd6f2e0c (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8031-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8031-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-6 (opens in a new tab)
- ubuntu.com/security/notices/USN-8031-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8052-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-7 (opens in a new tab)
- ubuntu.com/security/notices/USN-8028-8 (opens in a new tab)
- ubuntu.com/security/notices/USN-8052-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8074-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8074-2 (opens in a new tab)