CVE-2025-21692: Linux kernel · net: sched: fix ets qdisc OOB
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1080.87~20.04.1 : patch Linux kernel soon.
Data as of 12 Nov 2026, 19:10 UTC
- Patch
- Available – fixed in 5.15.0-1080.87~20.04.1, 5.15.0-1086.95~20.04.1, 5.15.0-1081.90~20.04.1 +62
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 10 Feb 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-7387-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7388-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7389-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7390-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7387-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7387-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7407-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7421-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7445-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7448-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7458-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7459-1 (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 is available and should be applied promptly. The vulnerability is fixed in Linux kernel versions 5.15.0-1074.77~20.04.1 and later, including other 5.15.x releases listed in the established fixed versions. Users and administrators should update their Linux kernel packages to these fixed versions or later as provided by their distribution vendors. No additional mitigations are specified beyond applying the official kernel updates.
Description
CVE-2025-21692 is a high-severity vulnerability in the Linux kernel's ETS queuing discipline (qdisc) scheduler. It involves an out-of-bounds indexing issue in the ets_class_from_arg() function when passed a class ID of 0, which can lead to a local privilege escalation. The flaw was identified by Haowei Yan and results in an array index out-of-bounds error. Multiple affected Linux kernel versions exist, primarily in the 5.15 and earlier series. Official patches have been released to address this vulnerability.
References
- ubuntu.com/security/CVE-2025-21692 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-21692 (opens in a new tab)
- git.kernel.org/linus/d62b04fca4340a0d468d7853bd66e511935a18cb (opens in a new tab)
- git.kernel.org/stable/c/03c56665dab1f4ac844bc156652d50d639093fa5 (opens in a new tab)
- git.kernel.org/stable/c/1332c6ed446be787f901ed1064ec6a3c694f028a (opens in a new tab)
- git.kernel.org/stable/c/997f6ec4208b23c87daf9f044689685f091826f7 (opens in a new tab)
- git.kernel.org/stable/c/bcf0d815e728a3a304b50455b32a3170c16e1eaa (opens in a new tab)
- git.kernel.org/stable/c/d62b04fca4340a0d468d7853bd66e511935a18cb (opens in a new tab)
- git.kernel.org/stable/c/f4168299e553f17aa2ba4016e77a9c38da40eb1d (opens in a new tab)
- git.kernel.org/stable/c/f6b0f05fbfa4044f890e8a348288c0d9a20bd1d0 (opens in a new tab)
- ubuntu.com/security/notices/USN-7387-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7388-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7389-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7390-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7387-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7387-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7407-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7421-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7445-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7448-1 (opens in a new tab)