CVE-2025-37938: debian linux Null Dereference — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: tracing: Verify event formats that have "%*p.." The trace event verifier checks the formats of trace events to make sure that they do not point at memory that is not in the trace event itself or in data that will never be freed. If an event references data that was allocated when the event triggered and that same data is freed before the event is read, then the kernel can crash by reading freed memory. The verifier runs at boot up (or module load) and scans the print formats of the events and checks their arguments to make sure that dereferenced pointers are safe. If the format uses "%*p.." the verifier will ignore it, and that could be dangerous. Cover this case as well. Also add to the sample code a use case of "%*pbl".

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.13 — 6.1.136
linux	linux_kernel	6.2 — 6.6.89
linux	linux_kernel	6.7 — 6.12.26
linux	linux_kernel	6.13 — 6.13.11
linux	linux_kernel	6.14 — 6.14.2
debian	debian_linux	All

References

Advisories & Patches

https://git.kernel.org/stable/c/03127354027508d076073b020d3070990fd6a958 https://git.kernel.org/stable/c/04b80d45ecfaf780981d6582899e3ab205e4aa08 https://git.kernel.org/stable/c/4d11fac941d83509be4e6a21038281d6d96da50c https://git.kernel.org/stable/c/6854c87ac823181c810f8c07489ba543260c0023 https://git.kernel.org/stable/c/c7204fd1758c0caf1938e8a59809a1fdf28a8114 https://git.kernel.org/stable/c/ea8d7647f9ddf1f81e2027ed305299797299aa03

Other References

https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html

Frequently Asked Questions

What is CVE-2025-37938? +

In the Linux kernel, the following vulnerability has been resolved: tracing: Verify event formats that have "%*p.." The trace event verifier checks the formats of trace events to make sure that they do not point at memory that is not in the trace event itself or in data that will never be freed. If an event references data that was allocated when the event triggered and that same data is freed before the event is read, then the kernel can crash by reading freed memory. The verifier runs at boot up (or module load) and scans the print formats of the events and checks their arguments to make sure that dereferenced pointers are safe. If the format uses "%*p.." the verifier will ignore it, and that could be dangerous. Cover this case as well. Also add to the sample code a use case of "%*pbl". It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2025-37938? +

CVE-2025-37938 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-37938? +

CVE-2025-37938 affects products from debian, linux, specifically: debian_linux, linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-37938? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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