CVE-2025-38004: debian linux Out-of-bounds Read — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: can: bcm: add locking for bcm_op runtime updates The CAN broadcast manager (CAN BCM) can send a sequence of CAN frames via hrtimer. The content and also the length of the sequence can be changed resp reduced at runtime where the 'currframe' counter is then set to zero. Although this appeared to be a safe operation the updates of 'currframe' can be triggered from user space and hrtimer context in bcm_can_tx(). Anderson Nascimento created a proof of concept that triggered a KASAN slab-out-of-bounds read access which can be prevented with a spin_lock_bh. At the rework of bcm_can_tx() the 'count' variable has been moved into the protected section as this variable can be modified from both contexts too.

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CVSS v3.1 Score

7.1

HIGH

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

Weakness Type (CWE)

CWE-125 Out-of-bounds Read

Affected Products

Vendor	Product	Versions
linux	linux_kernel	2.6.25 — 5.4.294
linux	linux_kernel	5.5 — 5.10.238
linux	linux_kernel	5.11 — 5.15.185
linux	linux_kernel	5.16 — 6.1.141
linux	linux_kernel	6.2 — 6.6.93
linux	linux_kernel	6.7 — 6.12.31
linux	linux_kernel	6.13 — 6.14.9
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
debian	debian_linux	All

References

Advisories & Patches

https://git.kernel.org/stable/c/2a437b86ac5a9893c902f30ef66815bf13587bf6 https://git.kernel.org/stable/c/7595de7bc56e0e52b74e56c90f7e247bf626d628 https://git.kernel.org/stable/c/76c84c3728178b2d38d5604e399dfe8b0752645e https://git.kernel.org/stable/c/8f1c022541bf5a923c8d6fa483112c15250f30a4 https://git.kernel.org/stable/c/c2aba69d0c36a496ab4f2e81e9c2b271f2693fd7 https://git.kernel.org/stable/c/c4e8a172501e677ebd8ea9d9161d97dc4df56fbd https://git.kernel.org/stable/c/cc55dd28c20a6611e30596019b3b2f636819a4c0 https://git.kernel.org/stable/c/fbd8fdc2b218e979cfe422b139b8f74c12419d1f

Other References

https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html

Frequently Asked Questions

What is CVE-2025-38004? +

In the Linux kernel, the following vulnerability has been resolved: can: bcm: add locking for bcm_op runtime updates The CAN broadcast manager (CAN BCM) can send a sequence of CAN frames via hrtimer. The content and also the length of the sequence can be changed resp reduced at runtime where the 'currframe' counter is then set to zero. Although this appeared to be a safe operation the updates of 'currframe' can be triggered from user space and hrtimer context in bcm_can_tx(). Anderson Nascimento created a proof of concept that triggered a KASAN slab-out-of-bounds read access which can be prevented with a spin_lock_bh. At the rework of bcm_can_tx() the 'count' variable has been moved into the protected section as this variable can be modified from both contexts too. It has a CVSS v3.1 base score of 7.1 (HIGH).

How severe is CVE-2025-38004? +

CVE-2025-38004 has a CVSS v3.1 score of 7.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-38004? +

CVE-2025-38004 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-2025-38004? +

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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