CVE-2026-74663
In the Linux kernel, the following vulnerability has been resolved: net/sched: reject overly deep qdisc hierarchies Deep qdisc hierarchies can lead to excessive recursion in qdisc tree walkers and exhaust the kernel stack. The existing loop check does not cover the create-and-graft path, so a hierarchy can still be extended by creating a new child qdisc below an already deep parent. Store the hierarchy depth in struct Qdisc and update it when qdiscs are grafted. Reject new child qdiscs once the parent is already at the maximum allowed depth.
Affected versions
Linux kernel versions
2.6.12
and later are affected. Fixed in
6.1.183,
6.6.152,
6.12.104,
6.18.45,
7.1.9,
7.2
and their respective stable series.
References
6 totalFrequently asked questions
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What is CVE-2026-74663?
CVE-2026-74663 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 2.6.12 onward and has been patched in 6.1.183, 6.6.152, 6.12.104 and others. CVE-2026-74663 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-74663?
Yes. CVE-2026-74663 has been patched. Fixed versions include 6.1.183, 6.6.152, 6.12.104 and others. If you are running Linux kernel 2.6.12 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-74663 actively exploited?
No. CVE-2026-74663 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.