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

Published Jan 25, 2026
·
Updated

In the Linux kernel, the following vulnerability has been resolved:

net/sched: schqfq: do not free existing class in qfqchangeclass()

Fixes qfqchangeclass() error case.

cl->qdisc and cl should only be freed if a new class and qdisc were allocated, or we risk various UAF.

Affected Software

13 affected componentsFixes available
linux/kernel
Linux Linux kernel>=3.8<5.10.249
Linux Linux kernel>=5.11<5.15.199
Linux Linux kernel>=5.16<6.1.162
Linux Linux kernel>=6.2<6.6.122
Linux Linux kernel>=6.7<6.12.67
Linux Linux kernel>=6.13<6.18.7
Linux Linux kernel=6.19-rc1
Linux Linux kernel=6.19-rc2
Linux Linux kernel=6.19-rc3
Linux Linux kernel=6.19-rc4
Linux Linux kernel=6.19-rc5
Microsoft cbl2 kernel 5.15.186.1-1

Event History

Jan 25, 2026
CVE Published
via MITRE·02:36 PM
Data Sourced
via MITRE·02:36 PM
DescriptionSeverity
Data Sourced
via NVD·03:15 PM
RemedyDescriptionSeverityAffected Software
Feb 28, 2026
Data Sourced
via Microsoft·09:04 AM
DescriptionSeverityWeakness
Data Sourced
via Microsoft·09:04 AM
Affected Software
Updated
via Microsoft·09:04 AM
DescriptionSeverity

Frequently Asked Questions

1

What is the severity of CVE-2026-22999?

CVE-2026-22999 is classified as a medium severity vulnerability due to potential risks in the Linux kernel's scheduling mechanism.

2

How do I fix CVE-2026-22999?

Fix CVE-2026-22999 by updating to the latest version of the Linux kernel where this vulnerability has been resolved.

3

What are the consequences of not addressing CVE-2026-22999?

Failing to address CVE-2026-22999 may lead to unexpected behavior or instability in the system's scheduling functionality.

4

Which versions of the Linux kernel are affected by CVE-2026-22999?

CVE-2026-22999 affects multiple versions of the Linux kernel that implement the sch_qfq scheduling class.

5

Is CVE-2026-22999 exploitable remotely?

CVE-2026-22999 is not known to be exploitable remotely as it relates to local scheduling operations within the Linux kernel.

Contact

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