CVE-2025-37890

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 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/

Package Linux Kernel
Published 2025-05-16
Last modified 2025-11-17
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

7.8

out of 10
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness type

CWE-416

CVE-2025-37890 is a Use After Free vulnerability

What is Use After Free?

The product references memory after it has been freed, which may cause it to crash, use unexpected values, or execute code. Learn more on MITRE CWE

Affected versions

Linux kernel versions 5.0 and later are affected. Fixed in 5.4.294, 5.10.238, 5.15.182, 6.1.138, 6.6.90, 6.12.28, 6.14.6, 6.15 and their respective stable series.

Affected from
≥ 5.0
Fixed in
✓ 5.4.294 5.4.x ✓ 5.10.238 5.10.x ✓ 5.15.182 5.15.x ✓ 6.1.138 6.1.x ✓ 6.6.90 6.6.x ✓ 6.12.28 6.12.x ✓ 6.14.6 6.14.x ✓ 6.15

References

The following references provide additional information about CVE-2025-37890 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

8 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2025-37890?

    CVE-2025-37890 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 , classified as an Use After Free flaw (CWE-416) . It affects Linux kernel versions from 5.0 onward and has been patched in 5.4.294, 5.10.238, 5.15.182 and others. CVE-2025-37890 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2025-37890?

    CVE-2025-37890 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H .

  • Is there a patch available for CVE-2025-37890?

    Yes — CVE-2025-37890 has been patched. Fixed versions include 5.4.294, 5.10.238, 5.15.182 and others. If you are running Linux kernel 5.0 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2025-37890 actively exploited?

    No — CVE-2025-37890 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

  • What is Use After Free (CWE-416)?

    The product references memory after it has been freed, which may cause it to crash, use unexpected values, or execute code. View CWE-416 on MITRE CWE →

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