SB20260919162 - Improper input validation in Linux kernel sched

Description

This security bulletin contains information about 1 vulnerability.

1) Improper input validation (CVE-ID: CVE-2026-90050)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper input validation in the fq qdisc change path when processing TCA_FQ_QUANTUM and TCA_FQ_INITIAL_QUANTUM configuration attributes. A local user can configure a qdisc with a small quantum value to cause a denial of service.

Exploitation requires CAP_NET_ADMIN in the relevant network namespace and CONFIG_NET_SCH_FQ to be enabled.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/094cc07f98dfe70a34e2a1923af17fd29b8cf622
• https://git.kernel.org/stable/c/72e9387884554f47b03bfd40fb8b2bf52789c68d
• https://git.kernel.org/stable/c/798283cd0fe7ba997f67e5a917f14ab40afa8d9f
• https://git.kernel.org/stable/c/a27498d34c3f429fb6db3aa609569f8154afa175