CVE-2025-21919: Linux kernel · sched/fair: Fix potential memory corruption in child_cfs_rq_on_list
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1084.91~20.04.1 : patch Linux kernel soon.
Data as of 12 Nov 2026, 19:32 UTC
Sources agree
| CNA (Linux) | CVSS 3.1 | 7.8 |
|---|---|---|
| CISA-ADP | CVSS 3.1 | 7.8 |
- Patch
- Available – fixed in 5.15.0-1084.91~20.04.1, 5.15.0-1089.98~20.04.1, 5.15.0-1083.92~20.04.1 +66
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 1 Apr 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 12 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- ubuntu.com/security/notices/USN-7510-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7511-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7511-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7512-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7511-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-6 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-7 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-8 (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-nvidiapkg:deb/ubuntu/linux-azure-nvidia?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?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 addressing this vulnerability is available and included in Linux kernel versions 5.15.0-1084.91~20.04.1 and later. Users should update their Linux kernel to one of the fixed versions listed in the advisory and reboot their systems to apply the fix. No additional mitigation steps are required beyond applying the official update.
Description
CVE-2025-21919 is a high-severity vulnerability in the Linux kernel's fair scheduler subsystem that could lead to memory corruption. The flaw arises from an invalid pointer conversion in the child_cfs_rq_on_list function, which can cause memory faults or unpredictable behavior depending on the kernel's internal structure layout. This issue has been fixed in Linux kernel versions 5.15.0-1084.91~20.04.1 and later. Users should apply the official patches and reboot to mitigate the risk.
References
- ubuntu.com/security/CVE-2025-21919 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-21919 (opens in a new tab)
- git.kernel.org/linus/3b4035ddbfc8e4521f85569998a7569668cccf51 (opens in a new tab)
- git.kernel.org/stable/c/000c9ee43928f2ce68a156dd40bab7616256f4dd (opens in a new tab)
- git.kernel.org/stable/c/3b4035ddbfc8e4521f85569998a7569668cccf51 (opens in a new tab)
- git.kernel.org/stable/c/5cb300dcdd27e6a351ac02541e0231261c775852 (opens in a new tab)
- git.kernel.org/stable/c/9cc7f0018609f75a349e42e3aebc3b0e905ba775 (opens in a new tab)
- git.kernel.org/stable/c/b5741e4b9ef3567613b2351384f91d3f16e59986 (opens in a new tab)
- git.kernel.org/stable/c/e1dd09df30ba86716cb2ffab97dc35195c01eb8f (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7511-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7511-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7512-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7511-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-6 (opens in a new tab)
- ubuntu.com/security/notices/USN-7510-7 (opens in a new tab)