{"id":"CVE-2026-97566","summary":"mptcp: pm: kernel: drop pending ADD_ADDR when removing ID0","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: pm: kernel: drop pending ADD_ADDR when removing ID0\n\nThe in-kernel MPTCP path manager can leave a stale ADD_ADDR announcement\nentry alive when removing the id 0 endpoint. This happens because the id 0\nremoval path does not tear down pending announcements, unlike the non-zero\nid path.\n\nWhen the PM later reselects id 0 after adding another signal endpoint, it\nfinds the stale anno_list entry and hits WARN_ON_ONCE(mptcp_pm_is_kernel())\nin mptcp_pm_announced_alloc().\n\nRoot cause: asymmetry between removal paths.\n- Non-zero id path: mptcp_nl_remove_subflow_and_signal_addr() calls\n  mptcp_pm_remove_announced() to clean up.\n- Id 0 path: mptcp_nl_remove_id_zero_address() skips cleanup entirely.\n\nFix by making the id 0 path symmetric: call mptcp_pm_announced_remove()\nand decrement add_addr_signaled before queuing the RM_ADDR.\n\nSubtle detail: signal endpoints are stored in anno_list with port 0, but\nmsk_local carries the connection's local port. In other words, entries\nlinked to ID0 paths should have port == 0. A follow-up patch will ensure\nthat. mptcp_pm_announced_remove() uses use_port=true for comparison. So\nclear the port before the lookup.","modified":"2026-09-26T03:48:27.710082286Z","published":"2026-09-25T10:21:53.068Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97566.json","cna_assigner":"Linux"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2ac7d6e620764f1fc79eb4edd3610a7a661981ca"},{"type":"WEB","url":"https://git.kernel.org/stable/c/545616b4e7325be3c61fc082538cb06d14f7b1db"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d4a67a880654e1bfe318a31bea0bdbb026a09ade"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97566.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97566"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"740d798e8767d8a449902b1a1bbc70facfce19b5"},{"fixed":"d4a67a880654e1bfe318a31bea0bdbb026a09ade"},{"fixed":"545616b4e7325be3c61fc082538cb06d14f7b1db"},{"fixed":"2ac7d6e620764f1fc79eb4edd3610a7a661981ca"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97566.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.13.0"},{"fixed":"6.18.53"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97566.json"}}],"schema_version":"1.9.0"}