CVE-2025-37913
Medium
Elevated severity or exploit probability.
CVSS breakdown
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
| Attack Vector | L | Local |
| Attack Complexity | L | Low |
| Privileges Required | L | Low |
| User Interaction | N | None |
| Scope | U | Unchanged |
| Confidentiality | H | High |
| Integrity | H | High |
| Availability | H | High |
Timeline
- 2025-05-20 — Published (NVD)
- 2026-07-30 — Last modified (NVD)
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
References
- https://git.kernel.org/stable/c/005a479540478a820c52de098e5e767e63e36f0a
- https://git.kernel.org/stable/c/041f410aec2c1751ee22b8b73ba05d38c3a6a602
- https://git.kernel.org/stable/c/0aa23e0856b7cedb3c88d8e3d281c212c7e4fbeb
- https://git.kernel.org/stable/c/0bf32d6fb1fcbf841bb9945570e0e2a70072c00f
- https://git.kernel.org/stable/c/370218e8ce711684acc4cdd3cc3c6dd7956bc165
- https://git.kernel.org/stable/c/53bc0b55178bd59bdd4bcd16349505cabf54b1a2
- https://git.kernel.org/stable/c/a43783119e01849fbf2fe8855634e8989b240cb4
- https://git.kernel.org/stable/c/f139f37dcdf34b67f5bf92bc8e0f7f6b3ac63aa4
- https://lists.debian.org/debian-lts-announce/2025/08/msg00010.html
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html