{"id":"CVE-2026-23321","revision":"09003e2db5144c138c06a20e221ebac0","records":[{"revision":"09003e2db5144c138c06a20e221ebac0","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-23321","aliases":[],"title":"mptcp: pm: in-kernel: always mark signal+subflow endp as used","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: pm: in-kernel: always mark signal+subflow endp as used\n\nSyzkaller managed to find a combination of actions that was generating\nthis warning:\n\n msk->pm.local_addr_used == 0\n WARNING: net/mptcp/pm_kernel.c:1071 at __mark_subflow_endp_available net/mptcp/pm_kernel.c:1071 [inline], CPU#1: syz.2.17/961\n WARNING: net/mptcp/pm_kernel.c:1071 at mptcp_nl_remove_subflow_and_signal_addr net/mptcp/pm_kernel.c:1103 [inline], CPU#1: syz.2.17/961\n WARNING: net/mptcp/pm_kernel.c:1071 at mptcp_pm_nl_del_addr_doit+0x81d/0x8f0 net/mptcp/pm_kernel.c:1210, CPU#1: syz.2.17/961\n Modules linked in:\n CPU: 1 UID: 0 PID: 961 Comm: syz.2.17 Not tainted 6.19.0-08368-gfafda3b4b06b #22 PREEMPT(full)\n Hardware name: QEMU Ubuntu 25.10 PC v2 (i440FX + PIIX, + 10.1 machine, 1996), BIOS 1.17.0-debian-1.17.0-1build1 04/01/2014\n RIP: 0010:__mark_subflow_endp_available net/mptcp/pm_kernel.c:1071 [inline]\n RIP: 0010:mptcp_nl_remove_subflow_and_signal_addr net/mptcp/pm_kernel.c:1103 [inline]\n RIP: 0010:mptcp_pm_nl_del_addr_doit+0x81d/0x8f0 net/mptcp/pm_kernel.c:1210\n Code: 89 c5 e8 46 30 6f fe e9 21 fd ff ff 49 83 ed 80 e8 38 30 6f fe 4c 89 ef be 03 00 00 00 e8 db 49 df fe eb ac e8 24 30 6f fe 90 <0f> 0b 90 e9 1d ff ff ff e8 16 30 6f fe eb 05 e8 0f 30 6f fe e8 9a\n RSP: 0018:ffffc90001663880 EFLAGS: 00010293\n RAX: ffffffff82de1a6c RBX: 0000000000000000 RCX: ffff88800722b500\n RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000\n RBP: ffff8880158b22d0 R08: 0000000000010425 R09: ffffffffffffffff\n R10: ffffffff82de18ba R11: 0000000000000000 R12: ffff88800641a640\n R13: ffff8880158b1880 R14: ffff88801ec3c900 R15: ffff88800641a650\n FS: 00005555722c3500(0000) GS:ffff8880f909d000(0000) knlGS:0000000000000000\n CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 00007f66346e0f60 CR3: 000000001607c000 CR4: 0000000000350ef0\n Call Trace:\n \n genl_family_rcv_msg_doit+0x117/0x180 net/netlink/genetlink.c:1115\n genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]\n genl_rcv_msg+0x3a8/0x3f0 net/netlink/genetlink.c:1210\n netlink_rcv_skb+0x16d/0x240 net/netlink/af_netlink.c:2550\n genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219\n netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]\n netlink_unicast+0x3e9/0x4c0 net/netlink/af_netlink.c:1344\n netlink_sendmsg+0x4aa/0x5b0 net/netlink/af_netlink.c:1894\n sock_sendmsg_nosec net/socket.c:727 [inline]\n __sock_sendmsg+0xc9/0xf0 net/socket.c:742\n ____sys_sendmsg+0x272/0x3b0 net/socket.c:2592\n ___sys_sendmsg+0x2de/0x320 net/socket.c:2646\n __sys_sendmsg net/socket.c:2678 [inline]\n __do_sys_sendmsg net/socket.c:2683 [inline]\n __se_sys_sendmsg net/socket.c:2681 [inline]\n __x64_sys_sendmsg+0x110/0x1a0 net/socket.c:2681\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0x143/0x440 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n RIP: 0033:0x7f66346f826d\n Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48\n RSP: 002b:00007ffc83d8bdc8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e\n RAX: ffffffffffffffda RBX: 00007f6634985fa0 RCX: 00007f66346f826d\n RDX: 00000000040000b0 RSI: 0000200000000740 RDI: 0000000000000007\n RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000\n R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6634985fa8\n R13: 00007f6634985fac R14: 0000000000000000 R15: 0000000000001770\n \n\nThe actions that caused that seem to be:\n\n - Set the MPTCP subflows limit to 0\n - Create an MPTCP endpoint with both the 'signal' and 'subflow' flags\n - Create a new MPTCP connection from a different address: an ADD_ADDR\n linked to the MPTCP endpoint will be sent ('signal' flag), but no\n subflows is initiated ('subflow' flag)\n - Remove the MPTCP endpoint\n\n---truncated---","state":0,"publishedAt":"2026-03-25T10:27:15.125+00:00","modifiedAt":"2026-10-15T01:14:04.247+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"net/mptcp/pm_kernel.c\"\n ],\n \"versions\": [\n {\n \"version\": \"d93cf38fad9f66397093432b8917971a92ee0146\",\n \"lessThan\": \"c5c877e140e5f46023a74a51e577ce5edd0a4be7\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"64815ba15880ce5f99df075fa4104fef170ac7e5\",\n \"lessThan\": \"05799c2f1ca5eb13d65764dda688d02021b65e06\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"85df533a787bf07bf4367ce2a02b822ff1fba1a3\",\n \"lessThan\": \"67f34ab318807989b57dfdb0f79e2d4e57018290\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"85df533a787bf07bf4367ce2a02b822ff1fba1a3\",\n \"lessThan\": \"a64aa7db39392add5be09dffaedbf1f0ce5554df\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"85df533a787bf07bf4367ce2a02b822ff1fba1a3\",\n \"lessThan\": \"198824ccfa64ffebd918bf99c939bd8170a4a4d8\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"85df533a787bf07bf4367ce2a02b822ff1fba1a3\",\n \"lessThan\": \"579a752464a64cb5f9139102f0e6b90a1f595ceb\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"0f21cc29bc13e86512621727a4388c8a7ad2716b\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"6.1.106\",\n \"lessThan\": \"6.1.167\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.46\",\n \"lessThan\": \"6.6.130\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.10.5\",\n \"lessThan\": \"6.11\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"net/mptcp/pm_kernel.c\"\n ],\n \"versions\": [\n {\n \"version\": \"6.11\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"6.11\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.167\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.130\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.78\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.17\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.19.7\",\n \"lessThanOrEqual\": \"6.19.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.0\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/c5c877e140e5f46023a74a51e577ce5edd0a4be7","https://git.kernel.org/stable/c/05799c2f1ca5eb13d65764dda688d02021b65e06","https://git.kernel.org/stable/c/67f34ab318807989b57dfdb0f79e2d4e57018290","https://git.kernel.org/stable/c/a64aa7db39392add5be09dffaedbf1f0ce5554df","https://git.kernel.org/stable/c/198824ccfa64ffebd918bf99c939bd8170a4a4d8","https://git.kernel.org/stable/c/579a752464a64cb5f9139102f0e6b90a1f595ceb"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-23321","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-23321","identifiers":["CVE-2026-23321"]},"retained":false,"historicalAffected":[]}],"coverage":[]}