SB20260919144 - Integer overflow in Linux kernel sched

Description

This security bulletin contains information about 1 vulnerability.

1) Integer overflow (CVE-ID: CVE-2026-90076)

CWE-ID: CWE-190 - Integer overflow

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 an integer overflow in the fq qdisc initialization function fq_init() when initializing an fq qdisc for a device with a huge MTU. A local user can configure a device with an excessively large MTU to cause a denial of service.

Exploitation requires CAP_NET_ADMIN in a user namespace and an MTU plus hard_header_len large enough to make 2 * psched_mtu() wrap.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/709f34f7c28dc4dd6c40343d101850f11e172312
• https://git.kernel.org/stable/c/d16dac3925be95ad46e986d4b139c9898b6e227f
• https://git.kernel.org/stable/c/e35acd56f244d94355f9ab237c2ecc8fba5e6f04
• https://git.kernel.org/stable/c/f6b3e3848a5fca63438984acd6d9eceac80814c1