CVE-2025-37915

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

State: Published
Severity: 7.8 High
Published: May 20, 2025
Updated: Oct 15, 2026
Reserved: Apr 16, 2025

Description

In the Linux kernel, the following vulnerability has been resolved:

net_sched: drr: 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 drr, there won't be a UAF, but the code will add the same classifier to the list twice, which will cause memory corruption.

In addition to checking for qlen being zero, this patch checks whether the class was already added to the active_list (cl_is_active) before adding to the list to cover for the reentrant case.

[1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea to before 5da3aad1a13e7edb8ff0778a444ccf49930313e9Affected 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea to before 4b07ac06b0a712923255aaf2691637693fc7100dAffected 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea to before 2968632880f1792007eedd12eeedf7f6e2b7e9f3Affected 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea to before 4f0ecf50cdf76da95828578a92f130b653ac2fcfAffected 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea to before db205b92dfe0501e5b92fb7cf00971d0e44ba3ebAffected 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea to before 26e75716b94d6ff9be5ea07d63675c4d189f30b4Affected 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea to before ab2248110738d4429668140ad22f530a9ee730e1Affected 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea to before f99a3fbf023e20b626be4b0f042463d598050c9aAffected
LinuxLinux	5.0Affected before 5.0Not affected 5.4.294 through 5.4.Not affected 5.10.238 through 5.10.Not affected 5.15.182 through 5.15.Not affected 6.1.138 through 6.1.Not affected 6.6.90 through 6.6.Not affected 6.12.28 through 6.12.Not affected 6.14.6 through 6.14.*Not affected 6.15 and laterNot affected

Product

Versions

LinuxLinux

37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea to before 5da3aad1a13e7edb8ff0778a444ccf49930313e9Affected
37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea to before 4b07ac06b0a712923255aaf2691637693fc7100dAffected
37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea to before 2968632880f1792007eedd12eeedf7f6e2b7e9f3Affected
37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea to before 4f0ecf50cdf76da95828578a92f130b653ac2fcfAffected
37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea to before db205b92dfe0501e5b92fb7cf00971d0e44ba3ebAffected
37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea to before 26e75716b94d6ff9be5ea07d63675c4d189f30b4Affected
37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea to before ab2248110738d4429668140ad22f530a9ee730e1Affected
37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea to before f99a3fbf023e20b626be4b0f042463d598050c9aAffected

LinuxLinux

5.0Affected
before 5.0Not affected
5.4.294 through 5.4.*Not affected
5.10.238 through 5.10.*Not affected
5.15.182 through 5.15.*Not affected
6.1.138 through 6.1.*Not affected
6.6.90 through 6.6.*Not affected
6.12.28 through 6.12.*Not affected
6.14.6 through 6.14.*Not affected
6.15 and laterNot affected

References

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