{"cve":"CVE-2026-80784","nvd":{"published":"2026-09-04T16:18:04.333","modified":"2026-09-04T16:18:04.333","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: pm: fix memory leak from alloc-during-teardown race\n\nmptcp_pm_destroy() empties msk->pm.anno_list and\nmsk->pm.userspace_pm_local_addr_list under msk->pm.lock during socket\nteardown, dropping the lock between the two.\n\nA concurrent userspace PM genl ANNOUNCE on the same msk holds a sock\nreference via mptcp_token_get_sock() and, in\nmptcp_pm_nl_announce_doit(), calls\nmptcp_userspace_pm_append_new_local_addr() and\nmptcp_pm_announced_alloc(). Both take msk->pm.lock briefly to add to\ntheir respective lists. Because the genl handler holds a sock reference,\nmptcp_pm_destroy() may run on the same msk via mptcp_disconnect(), which\ninvokes mptcp_destroy_common() without dropping the sock refcount,\nbefore the handler completes.\n\nIf the lock acquisitions interleave such that mptcp_pm_destroy() empties\na list first, the later alloc adds its entry to a list head that nothing\nelse iterates for this msk, and the entry leaks. kmemleak reports both\nmptcp_pm_add_addr objects (from mptcp_pm_announced_alloc()) and\nmptcp_pm_addr_entry objects (from\nmptcp_userspace_pm_append_new_local_addr()) under sustained concurrent\nANNOUNCE + close load against the userspace PM.\n\nAdd an MPTCP_PM_DESTROYING bit in msk->pm.status, set by\nmptcp_pm_destroy() under pm.lock before the lists are emptied and\nchecked under pm.lock by the alloc paths. Either the alloc takes pm.lock\nfirst, in which case its entry is on the list when mptcp_pm_destroy()\nfrees it; or mptcp_pm_destroy() takes pm.lock first, in which case the\nlater alloc observes the bit and refuses.\n\nFound by an MPTCP protocol-flow harness extending BRF (arXiv:2305.08782).","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/6c290915a03fc8228b473641025cf762b256dbd2","https://git.kernel.org/stable/c/9fe5eebb664ecdba88f3fde18062d94b1d1c465f","https://git.kernel.org/stable/c/b2a0b55bf613bd3e81ed26a847b0f6b8e6b7f804","https://git.kernel.org/stable/c/bb32e9a6a9a9f99eeda16c4efe443400f3e43892","https://git.kernel.org/stable/c/efc33b5102ff859bacd390a5f30112d8e0c084c0"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:52:03.409947763+00:00"},"epss":{"cve":"CVE-2026-80784","score":0.00173,"percentile":0.06662,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}