CVE-2025-38460: atm: clip: Fix potential null-ptr-deref in to_atmarpd().

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-07-25 · updated 2026-10-15
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: atm: clip: Fix potential null-ptr-deref in to_atmarpd(). atmarpd is protected by RTNL since commit f3a0592b37b8 ("[ATM]: clip causes unregister hang"). However, it is not enough because to_atmarpd() is called without RTNL, especially clip_neigh_solicit() / neigh_ops->solicit() is unsleepable. Also, there is no RTNL dependency around atmarpd. Let's use a private mutex and RCU to protect access to atmarpd in to_atmarpd().

Affected products

Debian Linux: 11.0
Linux kernel: from 2.6.13 before 5.4.296; from 5.5 before 5.10.240; from 5.11 before 5.15.189; from 5.16 before 6.1.146; from 6.2 before 6.6.99; from 6.7 before 6.12.39 — fixed in 5.10.240, 5.15.189, 5.4.296, 6.1.146, 6.12.39, 6.15.7

How to fix

Upgrade to a fixed version: Linux kernel 5.10.240, 5.15.189, 5.4.296, 6.1.146. Check the vendor advisory for mitigations.

References

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