mptcp: Initialise rcv_mss before calling tcp_send_active_reset() in mptcp_do_fastclose().
Summary
| CVE | CVE-2025-68291 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2025-12-16 16:16:07 UTC |
| Updated | 2026-07-14 13:17:58 UTC |
| Description | In the Linux kernel, the following vulnerability has been resolved: mptcp: Initialise rcv_mss before calling tcp_send_active_reset() in mptcp_do_fastclose(). syzbot reported divide-by-zero in __tcp_select_window() by MPTCP socket. [0] We had a similar issue for the bare TCP and fixed in commit 499350a5a6e7 ("tcp: initialize rcv_mss to TCP_MIN_MSS instead of 0"). Let's apply the same fix to mptcp_do_fastclose(). [0]: Oops: divide error: 0000 [#1] SMP KASAN PTI CPU: 0 UID: 0 PID: 6068 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:__tcp_select_window+0x824/0x1320 net/ipv4/tcp_output.c:3336 Code: ff ff ff 44 89 f1 d3 e0 89 c1 f7 d1 41 01 cc 41 21 c4 e9 a9 00 00 00 e8 ca 49 01 f8 e9 9c 00 00 00 e8 c0 49 01 f8 44 89 e0 99 <f7> 7c 24 1c 41 29 d4 48 bb 00 00 00 00 00 fc ff df e9 80 00 00 00 RSP: 0018:ffffc90003017640 EFLAGS: 00010293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88807b469e40 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90003017730 R08: ffff888033268143 R09: 1ffff1100664d028 R10: dffffc0000000000 R11: ffffed100664d029 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 000055557faa0500(0000) GS:ffff888126135000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f64a1912ff8 CR3: 0000000072122000 CR4: 00000000003526f0 Call Trace: <TASK> tcp_select_window net/ipv4/tcp_output.c:281 [inline] __tcp_transmit_skb+0xbc7/0x3aa0 net/ipv4/tcp_output.c:1568 tcp_transmit_skb net/ipv4/tcp_output.c:1649 [inline] tcp_send_active_reset+0x2d1/0x5b0 net/ipv4/tcp_output.c:3836 mptcp_do_fastclose+0x27e/0x380 net/mptcp/protocol.c:2793 mptcp_disconnect+0x238/0x710 net/mptcp/protocol.c:3253 mptcp_sendmsg_fastopen+0x2f8/0x580 net/mptcp/protocol.c:1776 mptcp_sendmsg+0x1774/0x1980 net/mptcp/protocol.c:1855 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0xe5/0x270 net/socket.c:742 __sys_sendto+0x3bd/0x520 net/socket.c:2244 __do_sys_sendto net/socket.c:2251 [inline] __se_sys_sendto net/socket.c:2247 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2247 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f66e998f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffff9acedb8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f66e9be5fa0 RCX: 00007f66e998f749 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007ffff9acee10 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007f66e9be5fa0 R14: 00007f66e9be5fa0 R15: 0000000000000006 </TASK> |
Risk And Classification
EPSS: 0.001750000 probability, percentile 0.072130000 (date 2026-07-14)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 9ea05fabce31ff93a0adae8221c58bc6d7b832f3 46b8b58f93f1b383c3840fc6e8fab6c3bce9295f git | Not specified |
| CNA | Linux | Linux | affected 3a13454fd098ed51e733958488f8ec62859a9ed8 eee39f83246a81d970a9ecb7392b7ab74e660094 git | Not specified |
| CNA | Linux | Linux | affected f6fb2cbc91a81178dea23d463503b4525a76825d 05f5e26d488cdc7abc2a826cf1071782d5a21203 git | Not specified |
| CNA | Linux | Linux | affected c4f7b0916b95fd2226e5ab98882482b08f52e1c0 88163f85d59b4164884df900ee171720fd26686b git | Not specified |
| CNA | Linux | Linux | affected ae155060247be8dcae3802a95bd1bdf93ab3215d f07f4ea53e22429c84b20832fa098b5ecc0d4e35 git | Not specified |
| CNA | Linux | Linux | affected 6.1.159 6.1.160 semver | Not specified |
| CNA | Linux | Linux | affected 6.6.119 6.6.120 semver | Not specified |
| CNA | Linux | Linux | affected 6.12.60 6.12.61 semver | Not specified |
| CNA | Linux | Linux | affected 6.17.10 6.17.11 semver | Not specified |
| ADP | Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP | affected V3.1.6 * custom | Not specified |
| ADP | Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP | affected V3.1.6 * custom | Not specified |
| ADP | Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP | affected V3.1.6 * custom | Not specified |
| ADP | Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP | affected V3.1.6 * custom | Not specified |
| ADP | Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP | affected V3.1.6 * custom | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/05f5e26d488cdc7abc2a826cf1071782d5a21203 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| cert-portal.siemens.com/productcert/html/ssa-019113.html | 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e | cert-portal.siemens.com | |
| git.kernel.org/stable/c/88163f85d59b4164884df900ee171720fd26686b | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/f07f4ea53e22429c84b20832fa098b5ecc0d4e35 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/46b8b58f93f1b383c3840fc6e8fab6c3bce9295f | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/eee39f83246a81d970a9ecb7392b7ab74e660094 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.