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Unrated severityNVD Advisory· Published May 20, 2025· Updated Nov 3, 2025

net_sched: qfq: Fix double list add in class with netem as child qdisc

CVE-2025-37913

Description

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

88

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

8

News mentions

0

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