CVE-2026-74267: Linux kernel · net/sched: sch_codel: Do not call qdisc_tree_reduce_backlog during peek before
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.8 Critical · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 53% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +43
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 15 Aug 2026
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 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther 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 kernel versions to correct the call order in sch_codel. The fix prevents improper deactivation of the parent's class and wild memory access. Users should update to patched linux-aws kernel versions as provided by their vendor. No additional mitigations are specified or required beyond applying the official fix.
Description
A vulnerability in the Linux kernel's sch_codel network scheduler was fixed. The issue involved improper calling of qdisc_tree_reduce_backlog during the peek operation before restoring the queue length (qlen). This could cause the parent class to be mistakenly deactivated, leading to wild memory access and kernel crashes. The flaw affects specific linux-aws kernel versions and has a high CVSS score of 9.8. A patch is available to correct the call order, preventing this issue.
References
- nvd.nist.gov/vuln/detail/CVE-2026-74267 (opens in a new tab)
- git.kernel.org/stable/c/52f1da34c9f4d5bdc1e8b44242da5c7ba8db85f3 (opens in a new tab)
- git.kernel.org/stable/c/755108bb7a5083e911294c416cfea605dc75632f (opens in a new tab)
- git.kernel.org/stable/c/7a05af7f58566682b73578b72ca8e53a268c43bd (opens in a new tab)
- git.kernel.org/stable/c/91e0a793a72374c20ab31a40ccec21373e82e973 (opens in a new tab)
- git.kernel.org/stable/c/bb9cfd874ee884117b33e92a002b9a45b48202f4 (opens in a new tab)
- git.kernel.org/stable/c/e4615aa6bb7802944ae790cb4b3ef8c1b7491af3 (opens in a new tab)
- git.kernel.org/stable/c/e8c6dbadf139cb14ea6ed14add6ed6e88504dedd (opens in a new tab)
- git.kernel.org/stable/c/eba49fd85995a3851c597fa2d214f8d21736e1d8 (opens in a new tab)
- ubuntu.com/security/CVE-2026-74267 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-74267 (opens in a new tab)
- git.kernel.org/linus/52f1da34c9f4d5bdc1e8b44242da5c7ba8db85f3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8781-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8816-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8816-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8816-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8816-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8876-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8878-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8877-1 (opens in a new tab)