CVE-2025-37913: Debian Linux

High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: net_sched: qfq: Fix double list add in class with netem as child qdisc As described in Gerrard's report [1], there are use cases where a netem child qdisc will make the parent qdisc's enqueue callback reentrant. In the case of qfq, there won't be a UAF, but the code will add the same classifier to the list twice, which will cause memory corruption. This patch checks whether the class was already added to the agg->active list (cl_is_active) before doing the addition to cater for the reentrant case. [1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/

Affected products

• Debian Debian Linux: version 11.0 only
• Linux Linux Kernel: from 5.0.1, before 5.4.294 (fixed in 5.4.294); from 5.5, before 5.10.238 (fixed in 5.10.238); from 5.11, before 5.15.182 (fixed in 5.15.182); from 5.16, before 6.1.138 (fixed in 6.1.138); from 6.2, before 6.6.90 (fixed in 6.6.90); from 6.7, before 6.12.28 (fixed in 6.12.28); …

Published 2025-05-20. Last modified 2026-07-30.