CVE-2025-37913

HIGH
2025-05-20 416baaa9-dc9f-4396-8d5f-8c081fb06d67
7.8
CVSS 3.1
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CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

3
Analysis Generated
Mar 28, 2026 - 18:42 vuln.today
Patch Released
Mar 28, 2026 - 18:42 nvd
Patch available
CVE Published
May 20, 2025 - 16:15 nvd
HIGH 7.8

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/

Analysis

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. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity.

Technical Context

This vulnerability is classified under CWE-415. 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 include: Linux Linux Kernel, Debian Debian Linux.

Affected Products

Linux Linux Kernel, Debian Debian Linux.

Remediation

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Priority Score

39
Low Medium High Critical
KEV: 0
EPSS: +0.1
CVSS: +39
POC: 0

Vendor Status

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CVE-2025-37913 vulnerability details – vuln.today

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