What’s Vulnerable › Vulnerabilities

CVE-2026-23105: net/sched: qfq: Use cl_is_active to determine whether class is active in qfq_rm_from_ag

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-02-04 · updated 2026-10-19
• Weakness: CWE-20

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: qfq: Use cl_is_active to determine whether class is active in qfq_rm_from_ag This is more of a preventive patch to make the code more consistent and to prevent possible exploits that employ child qlen manipulations on qfq. use cl_is_active instead of relying on the child qdisc's qlen to determine class activation.

Affected products

• Linux kernel: from 3.8 before 5.10.249; from 5.11 before 5.15.199; from 5.16 before 6.1.162; from 6.2 before 6.6.122; from 6.7 before 6.12.68; from 6.13 before 6.18.8 — fixed in 5.10.249, 5.15.199, 6.1.162, 6.12.68, 6.18.8, 6.6.122

How to fix

Upgrade to a fixed version: Linux kernel 5.10.249, 5.15.199, 6.1.162, 6.12.68. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/77f1afd0bb4d5da95236f6114e6d0dfcde187ff6
• https://git.kernel.org/stable/c/93b8635974fb050c43d07e35e5edfe6e685ca28a
• https://git.kernel.org/stable/c/abd9fc26ea577561a5ef6241a1b058755ffdad0c
• https://git.kernel.org/stable/c/b8c24cf5268fb3bfb8d16324c3dbb985f698c835
• https://git.kernel.org/stable/c/d837fbee92453fbb829f950c8e7cf76207d73f33
• https://git.kernel.org/stable/c/f27047abf7cac1b6f90c3ad60de21ef9f717c26d
• https://git.kernel.org/stable/c/fac2c67bb2bb732eae4283e45fc338af7e08c254

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