What’s Vulnerable › Vulnerabilities

CVE-2026-22999: net/sched: sch_qfq: do not free existing class in qfq_change_class()

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-01-25 · updated 2026-10-19
• Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_qfq: do not free existing class in qfq_change_class() Fixes qfq_change_class() error case. cl->qdisc and cl should only be freed if a new class and qdisc were allocated, or we risk various UAF.

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 6.12.67; from 6.13 before 6.18.7 — fixed in 5.10.249, 5.15.199, 6.1.162, 6.12.67, 6.18.7, 6.6.122

How to fix

Upgrade to a fixed version: Linux kernel 5.10.249, 5.15.199, 6.1.162, 6.12.67. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/0a234660dc70ce45d771cbc76b20d925b73ec160
• https://git.kernel.org/stable/c/2a64fb9b47afffeb5dbab5fd3a518e1436dcc90e
• https://git.kernel.org/stable/c/362e269bb03f7076ba9990e518aeddb898232e50
• https://git.kernel.org/stable/c/3879cffd9d07aa0377c4b8835c4f64b4fb24ac78
• https://git.kernel.org/stable/c/cff6cd703f41d8071995956142729e4bba160363
• https://git.kernel.org/stable/c/e9d8f11652fa08c647bf7bba7dd8163241a332cd
• https://git.kernel.org/stable/c/f06f7635499bc806cbe2bbc8805c7cef8b1edddf

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