CVE-2025-38273: net: tipc: fix refcount warning in tipc_aead_encrypt

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: 2025-07-10 · updated 2026-07-30

Description

In the Linux kernel, the following vulnerability has been resolved: net: tipc: fix refcount warning in tipc_aead_encrypt syzbot reported a refcount warning [1] caused by calling get_net() on a network namespace that is being destroyed (refcount=0). This happens when a TIPC discovery timer fires during network namespace cleanup. The recently added get_net() call in commit e279024617134 ("net/tipc: fix slab-use-after-free Read in tipc_aead_encrypt_done") attempts to hold a reference to the network namespace. However, if the namespace is already being destroyed, its refcount might be zero, leading to the use-after-free warning. Replace get_net() with maybe_get_net(), which safely checks if the refcount is non-zero before incrementing it. If the namespace is being destroyed, return -ENODEV early, after releasing the bearer reference. [1]: https://lore.kernel.org/all/68342b55.a70a0220.253bc2.0091.GAE@google.com/T/#m12019cf9ae77e1954f666914640efa36d52704a2

Affected products

Debian Linux: 11.0
Linux kernel: from 6.12.31 before 6.12.34; from 6.14.9 before 6.15; from 6.15.1 before 6.15.3; 5.10.238, 5.15.185, 6.1.141, 6.6.93, 6.15 — fixed in 6.12.34, 6.15, 6.15.3

How to fix

Upgrade to a fixed version: Linux kernel 6.12.34, 6.15, 6.15.3. Check the vendor advisory for mitigations.

References

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