CVE-2026-80784

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

mptcp: pm: fix memory leak from alloc-during-teardown race

mptcp_pm_destroy() empties msk->pm.anno_list and

msk->pm.userspace_pm_local_addr_list under msk->pm.lock during socket

teardown, dropping the lock between the two.

A concurrent userspace PM genl ANNOUNCE on the same msk holds a sock

reference via mptcp_token_get_sock() and, in

mptcp_pm_nl_announce_doit(), calls

mptcp_userspace_pm_append_new_local_addr() and

mptcp_pm_announced_alloc(). Both take msk->pm.lock briefly to add to

their respective lists. Because the genl handler holds a sock reference,

mptcp_pm_destroy() may run on the same msk via mptcp_disconnect(), which

invokes mptcp_destroy_common() without dropping the sock refcount,

before the handler completes.

If the lock acquisitions interleave such that mptcp_pm_destroy() empties

a list first, the later alloc adds its entry to a list head that nothing

else iterates for this msk, and the entry leaks. km

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References