CVE-2026-46170: mptcp: pm: ADD_ADDR rtx: free sk if last

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: free sk if last When an ADD_ADDR is retransmitted, the sk is held in sk_reset_timer(), and released at the end. If at that moment, it was the last reference being held, the sk would not be freed. sock_put() should then be called instead of __sock_put(). But that's not enough: if it is the last reference, sock_put() will call sk_free(), which will end up calling sk_stop_timer_sync() on the same timer, and waiting indefinitely to finish. So it is needed to mark that the timer is done at the end of the timer handler when it has not been rescheduled, not to call sk_stop_timer_sync() on "itself".

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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