Go to homepageCyberStrike

Menu

Star on GitHub · 3.2k
Sign inDownload

CVE-2025-37890

7.8 · HIGH

In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Fix a UAF vulnerability in class with netem as child qdisc As described in Gerrard's report [1], we have a UAF…

Published May 16, 2025CWE-416EPSS 0.22%

Overview

CVE-2025-37890 is a high-severity vulnerability. It was published on May 16, 2025 and has a CVSS 3.1 base score of 7.8 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical description

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

net_sched: hfsc: Fix a UAF vulnerability in class with netem as child qdisc

As described in Gerrard's report [1], we have a UAF case when an hfsc class

has a netem child qdisc. The crux of the issue is that hfsc is assuming

that checking for cl->qdisc->q.qlen == 0 guarantees that it hasn't inserted

the class in the vttree or eltree (which is not true for the netem

duplicate case).

This patch checks the n_active class variable to make sure that the code

won't insert the class in the vttree or eltree twice, catering for the

reentrant case.

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

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/141d34391abbb315d68556b7c67ad97885407547Refgit.kernel.org/stable/c/273bbcfa53541cde38b2003ad88a59b770306421Refgit.kernel.org/stable/c/2e7093c7a8aba5d4f8809f271488e5babe75e202Refgit.kernel.org/stable/c/6082a87af4c52f58150d40dec1716011d871ac21Refgit.kernel.org/stable/c/8df7d37d626430035b413b97cee18396b3450befRefgit.kernel.org/stable/c/ac39fd4a757584d78ed062d4f6fd913f83bd98b5Refgit.kernel.org/stable/c/e0cf8ee23e1915431f262a7b2dee0c7a7d699af0Refgit.kernel.org/stable/c/e3e949a39a91d1f829a4890e7dfe9417ac72e4d0Reflists.debian.org/debian-lts-announce/2025/08/msg00010.htmlReflists.debian.org/debian-lts-announce/2025/10/msg00007.html

How CyberStrike helps

Frequently asked questions

What is CVE-2025-37890?

CVE-2025-37890 is a high-severity vulnerability. It was published on May 16, 2025 and has a CVSS 3.1 base score of 7.8 (HIGH).

How severe is CVE-2025-37890?

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2025-37890?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2025-37890?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2025-37890 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

Related HIGH CVEs from 2025

View all
Browse by year2026202520242023202220212020201920182017201620152014201320122011201020092008200720062005200420032002200120001999