SB20260928188 - Improper Validation of Specified Quantity in Input in Linux kernel sched

Description

This security bulletin contains information about 1 vulnerability.

1) Improper Validation of Specified Quantity in Input (CVE-ID: CVE-2026-98011)

CWE-ID: CWE-1284 - Improper Validation of Specified Quantity in Input

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/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 validation of the quantum value in the HHF queueing discipline when configuring an HHF qdisc with quantum set to 1 and a crafted size table. A local user can configure the qdisc with these values to cause a deficit-refill loop to spin under the qdisc lock and cause a denial of service.

Exploitation requires CONFIG_NET_SCH_HHF=y and CAP_NET_ADMIN in a network namespace.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/0898c6f9fa9ce2632ae88bd0f34a878ccc6335af
• https://git.kernel.org/stable/c/1113b674307ffddd402524bd1fd9d7d5629b705b
• https://git.kernel.org/stable/c/2e77947bbf6c166e76c038663832d0914418f761
• https://git.kernel.org/stable/c/eb56a495f59baf6cad5ed80e3ffb9078098b1346