CVE-2026-46158: mptcp: pm: ADD_ADDR rtx: always decrease sk refcount

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-28 · updated 2026-09-14

Description

In the Linux kernel, the following vulnerability has been resolved: mptcp: pm: ADD_ADDR rtx: always decrease sk refcount When an ADD_ADDR is retransmitted, the sk is held in sk_reset_timer(). It should then be released in all cases at the end. Some (unlikely) checks were returning directly instead of calling sock_put() to decrease the refcount. Jump to a new 'exit' label to call __sock_put() (which will become sock_put() in the next commit) to fix this potential leak. While at it, drop the '!msk' check which cannot happen because it is never reset, and explicitly mark the remaining one as "unlikely".

Affected products

Linux kernel: from 5.10 before 6.6.142; from 6.7 before 6.12.92; from 6.13 before 6.18.30; from 6.19 before 7.0.7; 7.1-rc1, 7.1-rc2 — fixed in 6.12.92, 6.18.30, 6.6.142, 7.0.7

How to fix

Upgrade to a fixed version: Linux kernel 6.12.92, 6.18.30, 6.6.142, 7.0.7. Check the vendor advisory for mitigations.

References

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