CVE-2026-98427EPSS p8.9%
CVE-2026-98427CVE-2026-98427
Description
In the Linux kernel, the following vulnerability has been resolved:
net/sched: codel: bound the dropping loop per dequeue call
The CoDel control law schedules the next drop one interval/sqrt(count)
after the previous drop, using the configured interval
(codel_params.interval). For very small intervals the scheduled step
rounds down to zero, so the dropping loop in codel_dequeue() never
advances and drains the entire backlog under the qdisc lock in one
call - an unprivileged user can trigger a soft lockup this way.
Fix in the shared codel code used by both codel and fq_codel:
1. Make the control-law step at least 1 tick so the dropping loop
always moves forward.
2. Cap the dropping loop at CODEL_MAX_DROPS_PER_DEQUEUE (256) drops
per codel_dequeue() call, resyncing drop_next to now when the cap
is hit: the catch-up owed to the loop grows with the idle gap and
the backlog, which no interval threshold can bound. This is a
deliberate behaviour change after long idle gaps
Scoring
| EPSS | 0.20% probability of exploitation · percentile 8.9% · 2026-10-17T12:00:28Z |
| Last modified | 2026-10-14 |