CVE-2026-90075

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description An issue exists in the fq codel init() function where the q->quantum and q->cparams.mtu values are set using psched mtu() without proper clamping. When a device is configured with an excessively large Maximum Transmission Unit (MTU), psched mtu() can return a value that overflows the signed flow->deficit variable to INT MIN within the fq codel dequeue() function. This leads to an infinite loop and a subsequent soft lockup. Additionally, an unclamped MTU value can cause the codel should drop() function to always evaluate as true, effectively disabling CoDel (Controlled Delay) functionality, preventing packet drops and Explicit Congestion Notification (ECN). Exploitation requires CAP NET ADMIN privileges within a user namespace.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.