{"id":"DEBIAN-CVE-2025-21705","details":"In the Linux kernel, the following vulnerability has been resolved:  mptcp: handle fastopen disconnect correctly  Syzbot was able to trigger a data stream corruption:    WARNING: CPU: 0 PID: 9846 at net/mptcp/protocol.c:1024 __mptcp_clean_una+0xddb/0xff0 net/mptcp/protocol.c:1024   Modules linked in:   CPU: 0 UID: 0 PID: 9846 Comm: syz-executor351 Not tainted 6.13.0-rc2-syzkaller-00059-g00a5acdbf398 #0   Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024   RIP: 0010:__mptcp_clean_una+0xddb/0xff0 net/mptcp/protocol.c:1024   Code: fa ff ff 48 8b 4c 24 18 80 e1 07 fe c1 38 c1 0f 8c 8e fa ff ff 48 8b 7c 24 18 e8 e0 db 54 f6 e9 7f fa ff ff e8 e6 80 ee f5 90 \u003c0f\u003e 0b 90 4c 8b 6c 24 40 4d 89 f4 e9 04 f5 ff ff 44 89 f1 80 e1 07   RSP: 0018:ffffc9000c0cf400 EFLAGS: 00010293   RAX: ffffffff8bb0dd5a RBX: ffff888033f5d230 RCX: ffff888059ce8000   RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000   RBP: ffffc9000c0cf518 R08: ffffffff8bb0d1dd R09: 1ffff110170c8928   R10: dffffc0000000000 R11: ffffed10170c8929 R12: 0000000000000000   R13: ffff888033f5d220 R14: dffffc0000000000 R15: ffff8880592b8000   FS:  00007f6e866496c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033   CR2: 00007f6e86f491a0 CR3: 00000000310e6000 CR4: 00000000003526f0   DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000   DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400   Call Trace:    \u003cTASK\u003e    __mptcp_clean_una_wakeup+0x7f/0x2d0 net/mptcp/protocol.c:1074    mptcp_release_cb+0x7cb/0xb30 net/mptcp/protocol.c:3493    release_sock+0x1aa/0x1f0 net/core/sock.c:3640    inet_wait_for_connect net/ipv4/af_inet.c:609 [inline]    __inet_stream_connect+0x8bd/0xf30 net/ipv4/af_inet.c:703    mptcp_sendmsg_fastopen+0x2a2/0x530 net/mptcp/protocol.c:1755    mptcp_sendmsg+0x1884/0x1b10 net/mptcp/protocol.c:1830    sock_sendmsg_nosec net/socket.c:711 [inline]    __sock_sendmsg+0x1a6/0x270 net/socket.c:726    ____sys_sendmsg+0x52a/0x7e0 net/socket.c:2583    ___sys_sendmsg net/socket.c:2637 [inline]    __sys_sendmsg+0x269/0x350 net/socket.c:2669    do_syscall_x64 arch/x86/entry/common.c:52 [inline]    do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83    entry_SYSCALL_64_after_hwframe+0x77/0x7f   RIP: 0033:0x7f6e86ebfe69   Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 1f 00 00 90 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 \u003c48\u003e 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48   RSP: 002b:00007f6e86649168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e   RAX: ffffffffffffffda RBX: 00007f6e86f491b8 RCX: 00007f6e86ebfe69   RDX: 0000000030004001 RSI: 0000000020000080 RDI: 0000000000000003   RBP: 00007f6e86f491b0 R08: 00007f6e866496c0 R09: 0000000000000000   R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6e86f491bc   R13: 000000000000006e R14: 00007ffe445d9420 R15: 00007ffe445d9508    \u003c/TASK\u003e  The root cause is the bad handling of disconnect() generated internally by the MPTCP protocol in case of connect FASTOPEN errors.  Address the issue increasing the socket disconnect counter even on such a case, to allow other threads waiting on the same socket lock to properly error out.","modified":"2026-09-01T16:06:09.728499514Z","published":"2025-02-27T02:15:14.137Z","upstream":["CVE-2025-21705"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2025-21705"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.129-1"}]}],"versions":["6.1.106-1","6.1.106-2","6.1.106-3","6.1.112-1","6.1.115-1","6.1.119-1","6.1.123-1","6.1.124-1","6.1.128-1","6.1.27-1","6.1.37-1","6.1.38-1","6.1.38-2","6.1.38-2~bpo11+1","6.1.38-3","6.1.38-4","6.1.38-4~bpo11+1","6.1.52-1","6.1.55-1","6.1.55-1~bpo11+1","6.1.64-1","6.1.66-1","6.1.67-1","6.1.69-1","6.1.69-1~bpo11+1","6.1.76-1","6.1.76-1~bpo11+1","6.1.82-1","6.1.85-1","6.1.90-1","6.1.90-1~bpo11+1","6.1.94-1","6.1.94-1~bpo11+1","6.1.98-1","6.1.99-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2025-21705.json"}},{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.13-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2025-21705.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.13-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2025-21705.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}