CVE-2025-68291 (GCVE-0-2025-68291)

Vulnerability from cvelistv5 – Published: 2025-12-16 15:06 – Updated: 2026-05-11 21:50
VLAI
Title
mptcp: Initialise rcv_mss before calling tcp_send_active_reset() in mptcp_do_fastclose().
Summary
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>
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 9ea05fabce31ff93a0adae8221c58bc6d7b832f3 , < 46b8b58f93f1b383c3840fc6e8fab6c3bce9295f (git)
Affected: 3a13454fd098ed51e733958488f8ec62859a9ed8 , < eee39f83246a81d970a9ecb7392b7ab74e660094 (git)
Affected: f6fb2cbc91a81178dea23d463503b4525a76825d , < 05f5e26d488cdc7abc2a826cf1071782d5a21203 (git)
Affected: c4f7b0916b95fd2226e5ab98882482b08f52e1c0 , < 88163f85d59b4164884df900ee171720fd26686b (git)
Affected: ae155060247be8dcae3802a95bd1bdf93ab3215d , < f07f4ea53e22429c84b20832fa098b5ecc0d4e35 (git)
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Linux Linux Affected: 6.1.159 , < 6.1.160 (semver)
Affected: 6.6.119 , < 6.6.120 (semver)
Affected: 6.12.60 , < 6.12.61 (semver)
Affected: 6.17.10 , < 6.17.11 (semver)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/mptcp/protocol.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "46b8b58f93f1b383c3840fc6e8fab6c3bce9295f",
              "status": "affected",
              "version": "9ea05fabce31ff93a0adae8221c58bc6d7b832f3",
              "versionType": "git"
            },
            {
              "lessThan": "eee39f83246a81d970a9ecb7392b7ab74e660094",
              "status": "affected",
              "version": "3a13454fd098ed51e733958488f8ec62859a9ed8",
              "versionType": "git"
            },
            {
              "lessThan": "05f5e26d488cdc7abc2a826cf1071782d5a21203",
              "status": "affected",
              "version": "f6fb2cbc91a81178dea23d463503b4525a76825d",
              "versionType": "git"
            },
            {
              "lessThan": "88163f85d59b4164884df900ee171720fd26686b",
              "status": "affected",
              "version": "c4f7b0916b95fd2226e5ab98882482b08f52e1c0",
              "versionType": "git"
            },
            {
              "lessThan": "f07f4ea53e22429c84b20832fa098b5ecc0d4e35",
              "status": "affected",
              "version": "ae155060247be8dcae3802a95bd1bdf93ab3215d",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/mptcp/protocol.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6.1.160",
              "status": "affected",
              "version": "6.1.159",
              "versionType": "semver"
            },
            {
              "lessThan": "6.6.120",
              "status": "affected",
              "version": "6.6.119",
              "versionType": "semver"
            },
            {
              "lessThan": "6.12.61",
              "status": "affected",
              "version": "6.12.60",
              "versionType": "semver"
            },
            {
              "lessThan": "6.17.11",
              "status": "affected",
              "version": "6.17.10",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.160",
                  "versionStartIncluding": "6.1.159",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.120",
                  "versionStartIncluding": "6.6.119",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.61",
                  "versionStartIncluding": "6.12.60",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.17.11",
                  "versionStartIncluding": "6.17.10",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: Initialise rcv_mss before calling tcp_send_active_reset() in mptcp_do_fastclose().\n\nsyzbot reported divide-by-zero in __tcp_select_window() by\nMPTCP socket. [0]\n\nWe had a similar issue for the bare TCP and fixed in commit\n499350a5a6e7 (\"tcp: initialize rcv_mss to TCP_MIN_MSS instead\nof 0\").\n\nLet\u0027s apply the same fix to mptcp_do_fastclose().\n\n[0]:\nOops: divide error: 0000 [#1] SMP KASAN PTI\nCPU: 0 UID: 0 PID: 6068 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025\nRIP: 0010:__tcp_select_window+0x824/0x1320 net/ipv4/tcp_output.c:3336\nCode: 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 \u003cf7\u003e 7c 24 1c 41 29 d4 48 bb 00 00 00 00 00 fc ff df e9 80 00 00 00\nRSP: 0018:ffffc90003017640 EFLAGS: 00010293\nRAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88807b469e40\nRDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000\nRBP: ffffc90003017730 R08: ffff888033268143 R09: 1ffff1100664d028\nR10: dffffc0000000000 R11: ffffed100664d029 R12: 0000000000000000\nR13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000\nFS:  000055557faa0500(0000) GS:ffff888126135000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00007f64a1912ff8 CR3: 0000000072122000 CR4: 00000000003526f0\nCall Trace:\n \u003cTASK\u003e\n tcp_select_window net/ipv4/tcp_output.c:281 [inline]\n __tcp_transmit_skb+0xbc7/0x3aa0 net/ipv4/tcp_output.c:1568\n tcp_transmit_skb net/ipv4/tcp_output.c:1649 [inline]\n tcp_send_active_reset+0x2d1/0x5b0 net/ipv4/tcp_output.c:3836\n mptcp_do_fastclose+0x27e/0x380 net/mptcp/protocol.c:2793\n mptcp_disconnect+0x238/0x710 net/mptcp/protocol.c:3253\n mptcp_sendmsg_fastopen+0x2f8/0x580 net/mptcp/protocol.c:1776\n mptcp_sendmsg+0x1774/0x1980 net/mptcp/protocol.c:1855\n sock_sendmsg_nosec net/socket.c:727 [inline]\n __sock_sendmsg+0xe5/0x270 net/socket.c:742\n __sys_sendto+0x3bd/0x520 net/socket.c:2244\n __do_sys_sendto net/socket.c:2251 [inline]\n __se_sys_sendto net/socket.c:2247 [inline]\n __x64_sys_sendto+0xde/0x100 net/socket.c:2247\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7f66e998f749\nCode: 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 \u003c48\u003e 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48\nRSP: 002b:00007ffff9acedb8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c\nRAX: ffffffffffffffda RBX: 00007f66e9be5fa0 RCX: 00007f66e998f749\nRDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003\nRBP: 00007ffff9acee10 R08: 0000000000000000 R09: 0000000000000000\nR10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001\nR13: 00007f66e9be5fa0 R14: 00007f66e9be5fa0 R15: 0000000000000006\n \u003c/TASK\u003e"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T21:50:19.280Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/46b8b58f93f1b383c3840fc6e8fab6c3bce9295f"
        },
        {
          "url": "https://git.kernel.org/stable/c/eee39f83246a81d970a9ecb7392b7ab74e660094"
        },
        {
          "url": "https://git.kernel.org/stable/c/05f5e26d488cdc7abc2a826cf1071782d5a21203"
        },
        {
          "url": "https://git.kernel.org/stable/c/88163f85d59b4164884df900ee171720fd26686b"
        },
        {
          "url": "https://git.kernel.org/stable/c/f07f4ea53e22429c84b20832fa098b5ecc0d4e35"
        }
      ],
      "title": "mptcp: Initialise rcv_mss before calling tcp_send_active_reset() in mptcp_do_fastclose().",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-68291",
    "datePublished": "2025-12-16T15:06:12.095Z",
    "dateReserved": "2025-12-16T14:48:05.292Z",
    "dateUpdated": "2026-05-11T21:50:19.280Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2025-68291",
      "date": "2026-05-27",
      "epss": "0.00043",
      "percentile": "0.13241"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-68291\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-12-16T16:16:07.980\",\"lastModified\":\"2026-01-11T17:15:54.820\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nmptcp: Initialise rcv_mss before calling tcp_send_active_reset() in mptcp_do_fastclose().\\n\\nsyzbot reported divide-by-zero in __tcp_select_window() by\\nMPTCP socket. [0]\\n\\nWe had a similar issue for the bare TCP and fixed in commit\\n499350a5a6e7 (\\\"tcp: initialize rcv_mss to TCP_MIN_MSS instead\\nof 0\\\").\\n\\nLet\u0027s apply the same fix to mptcp_do_fastclose().\\n\\n[0]:\\nOops: divide error: 0000 [#1] SMP KASAN PTI\\nCPU: 0 UID: 0 PID: 6068 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)\\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025\\nRIP: 0010:__tcp_select_window+0x824/0x1320 net/ipv4/tcp_output.c:3336\\nCode: 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 \u003cf7\u003e 7c 24 1c 41 29 d4 48 bb 00 00 00 00 00 fc ff df e9 80 00 00 00\\nRSP: 0018:ffffc90003017640 EFLAGS: 00010293\\nRAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88807b469e40\\nRDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000\\nRBP: ffffc90003017730 R08: ffff888033268143 R09: 1ffff1100664d028\\nR10: dffffc0000000000 R11: ffffed100664d029 R12: 0000000000000000\\nR13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000\\nFS:  000055557faa0500(0000) GS:ffff888126135000(0000) knlGS:0000000000000000\\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\\nCR2: 00007f64a1912ff8 CR3: 0000000072122000 CR4: 00000000003526f0\\nCall Trace:\\n \u003cTASK\u003e\\n tcp_select_window net/ipv4/tcp_output.c:281 [inline]\\n __tcp_transmit_skb+0xbc7/0x3aa0 net/ipv4/tcp_output.c:1568\\n tcp_transmit_skb net/ipv4/tcp_output.c:1649 [inline]\\n tcp_send_active_reset+0x2d1/0x5b0 net/ipv4/tcp_output.c:3836\\n mptcp_do_fastclose+0x27e/0x380 net/mptcp/protocol.c:2793\\n mptcp_disconnect+0x238/0x710 net/mptcp/protocol.c:3253\\n mptcp_sendmsg_fastopen+0x2f8/0x580 net/mptcp/protocol.c:1776\\n mptcp_sendmsg+0x1774/0x1980 net/mptcp/protocol.c:1855\\n sock_sendmsg_nosec net/socket.c:727 [inline]\\n __sock_sendmsg+0xe5/0x270 net/socket.c:742\\n __sys_sendto+0x3bd/0x520 net/socket.c:2244\\n __do_sys_sendto net/socket.c:2251 [inline]\\n __se_sys_sendto net/socket.c:2247 [inline]\\n __x64_sys_sendto+0xde/0x100 net/socket.c:2247\\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\\n do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94\\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\\nRIP: 0033:0x7f66e998f749\\nCode: 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 \u003c48\u003e 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48\\nRSP: 002b:00007ffff9acedb8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c\\nRAX: ffffffffffffffda RBX: 00007f66e9be5fa0 RCX: 00007f66e998f749\\nRDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003\\nRBP: 00007ffff9acee10 R08: 0000000000000000 R09: 0000000000000000\\nR10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001\\nR13: 00007f66e9be5fa0 R14: 00007f66e9be5fa0 R15: 0000000000000006\\n \u003c/TASK\u003e\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/05f5e26d488cdc7abc2a826cf1071782d5a21203\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/46b8b58f93f1b383c3840fc6e8fab6c3bce9295f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/88163f85d59b4164884df900ee171720fd26686b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/eee39f83246a81d970a9ecb7392b7ab74e660094\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f07f4ea53e22429c84b20832fa098b5ecc0d4e35\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.