Vulnerability-Lookup

FKIE_CVE-2023-53490

Vulnerability from fkie_nvd - Published: 2025-10-01 12:15 - Updated: 2026-08-04 10:19

Severity

7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
4.7 (Medium) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: mptcp: fix disconnect vs accept race Despite commit 0ad529d9fd2b ("mptcp: fix possible divide by zero in recvmsg()"), the mptcp protocol is still prone to a race between disconnect() (or shutdown) and accept. The root cause is that the mentioned commit checks the msk-level flag, but mptcp_stream_accept() does acquire the msk-level lock, as it can rely directly on the first subflow lock. As reported by Christoph than can lead to a race where an msk socket is accepted after that mptcp_subflow_queue_clean() releases the listener socket lock and just before it takes destructive actions leading to the following splat: BUG: kernel NULL pointer dereference, address: 0000000000000012 PGD 5a4ca067 P4D 5a4ca067 PUD 37d4c067 PMD 0 Oops: 0000 [#1] PREEMPT SMP CPU: 2 PID: 10955 Comm: syz-executor.5 Not tainted 6.5.0-rc1-gdc7b257ee5dd #37 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014 RIP: 0010:mptcp_stream_accept+0x1ee/0x2f0 include/net/inet_sock.h:330 Code: 0a 09 00 48 8b 1b 4c 39 e3 74 07 e8 bc 7c 7f fe eb a1 e8 b5 7c 7f fe 4c 8b 6c 24 08 eb 05 e8 a9 7c 7f fe 49 8b 85 d8 09 00 00 <0f> b6 40 12 88 44 24 07 0f b6 6c 24 07 bf 07 00 00 00 89 ee e8 89 RSP: 0018:ffffc90000d07dc0 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff888037e8d020 RCX: ffff88803b093300 RDX: 0000000000000000 RSI: ffffffff833822c5 RDI: ffffffff8333896a RBP: 0000607f82031520 R08: ffff88803b093300 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000003e83 R12: ffff888037e8d020 R13: ffff888037e8c680 R14: ffff888009af7900 R15: ffff888009af6880 FS: 00007fc26d708640(0000) GS:ffff88807dd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000012 CR3: 0000000066bc5001 CR4: 0000000000370ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> do_accept+0x1ae/0x260 net/socket.c:1872 __sys_accept4+0x9b/0x110 net/socket.c:1913 __do_sys_accept4 net/socket.c:1954 [inline] __se_sys_accept4 net/socket.c:1951 [inline] __x64_sys_accept4+0x20/0x30 net/socket.c:1951 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x47/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Address the issue by temporary removing the pending request socket from the accept queue, so that racing accept() can't touch them. After depleting the msk - the ssk still exists, as plain TCP sockets, re-insert them into the accept queue, so that later inet_csk_listen_stop() will complete the tcp socket disposal.

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/511b90e39250135a7f900f1c3afbce25543018a2	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/b2b4c84eb7149f34c0f25f17042d095ba5357d68	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/ded9f5551ce5cafa3c41c794428c27a0d0a00542	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	6.3
linux	linux_kernel	6.5
linux	linux_kernel	6.5
linux	linux_kernel	6.5
linux	linux_kernel	6.5
linux	linux_kernel	6.5

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
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          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/mptcp/protocol.h",
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              "version": "6.2.13",
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          ],
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          "versions": [
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              "status": "unaffected",
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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix disconnect vs accept race\n\nDespite commit 0ad529d9fd2b (\"mptcp: fix possible divide by zero in\nrecvmsg()\"), the mptcp protocol is still prone to a race between\ndisconnect() (or shutdown) and accept.\n\nThe root cause is that the mentioned commit checks the msk-level\nflag, but mptcp_stream_accept() does acquire the msk-level lock,\nas it can rely directly on the first subflow lock.\n\nAs reported by Christoph than can lead to a race where an msk\nsocket is accepted after that mptcp_subflow_queue_clean() releases\nthe listener socket lock and just before it takes destructive\nactions leading to the following splat:\n\nBUG: kernel NULL pointer dereference, address: 0000000000000012\nPGD 5a4ca067 P4D 5a4ca067 PUD 37d4c067 PMD 0\nOops: 0000 [#1] PREEMPT SMP\nCPU: 2 PID: 10955 Comm: syz-executor.5 Not tainted 6.5.0-rc1-gdc7b257ee5dd #37\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014\nRIP: 0010:mptcp_stream_accept+0x1ee/0x2f0 include/net/inet_sock.h:330\nCode: 0a 09 00 48 8b 1b 4c 39 e3 74 07 e8 bc 7c 7f fe eb a1 e8 b5 7c 7f fe 4c 8b 6c 24 08 eb 05 e8 a9 7c 7f fe 49 8b 85 d8 09 00 00 \u003c0f\u003e b6 40 12 88 44 24 07 0f b6 6c 24 07 bf 07 00 00 00 89 ee e8 89\nRSP: 0018:ffffc90000d07dc0 EFLAGS: 00010293\nRAX: 0000000000000000 RBX: ffff888037e8d020 RCX: ffff88803b093300\nRDX: 0000000000000000 RSI: ffffffff833822c5 RDI: ffffffff8333896a\nRBP: 0000607f82031520 R08: ffff88803b093300 R09: 0000000000000000\nR10: 0000000000000000 R11: 0000000000003e83 R12: ffff888037e8d020\nR13: ffff888037e8c680 R14: ffff888009af7900 R15: ffff888009af6880\nFS:  00007fc26d708640(0000) GS:ffff88807dd00000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000000000000012 CR3: 0000000066bc5001 CR4: 0000000000370ee0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nCall Trace:\n \u003cTASK\u003e\n do_accept+0x1ae/0x260 net/socket.c:1872\n __sys_accept4+0x9b/0x110 net/socket.c:1913\n __do_sys_accept4 net/socket.c:1954 [inline]\n __se_sys_accept4 net/socket.c:1951 [inline]\n __x64_sys_accept4+0x20/0x30 net/socket.c:1951\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x47/0xa0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x6e/0xd8\n\nAddress the issue by temporary removing the pending request socket\nfrom the accept queue, so that racing accept() can\u0027t touch them.\n\nAfter depleting the msk - the ssk still exists, as plain TCP sockets,\nre-insert them into the accept queue, so that later inet_csk_listen_stop()\nwill complete the tcp socket disposal."
    }
  ],
  "id": "CVE-2023-53490",
  "lastModified": "2026-08-04T10:19:08.740",
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    "cvssMetricV31": [
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        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
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          "baseScore": 7.8,
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          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
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          "scope": "UNCHANGED",
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        "source": "nvd@nist.gov",
        "type": "Primary"
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  "published": "2025-10-01T12:15:52.107",
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    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2023-53490 (GCVE-0-2023-53490)

Vulnerability from cvelistv5 – Published: 2025-10-01 11:45 – Updated: 2026-08-05 09:14

Title

mptcp: fix disconnect vs accept race

Summary

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6665 records in the last 180 days details

References

3 references

URL	Tags
https://git.kernel.org/stable/c/ded9f5551ce5cafa3…
https://git.kernel.org/stable/c/b2b4c84eb7149f34c…
https://git.kernel.org/stable/c/511b90e39250135a7…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: b45d8f5375eda3ddc89fe529b58bb643917bd87b , < ded9f5551ce5cafa3c41c794428c27a0d0a00542 (git) Affected: 2a6a870e44dd88f1a6a2893c65ef756a9edfb4c7 , < b2b4c84eb7149f34c0f25f17042d095ba5357d68 (git) Affected: 2a6a870e44dd88f1a6a2893c65ef756a9edfb4c7 , < 511b90e39250135a7f900f1c3afbce25543018a2 (git) Affected: 64b66601308dae6105fbde964a339462a29c2a73 (git) Affected: 6.1.27 , < 6.1.46 (semver) Affected: 6.2.13 , < 6.3 (semver)
Linux	Linux	Affected: 6.3 Unaffected: 0 , < 6.3 (semver) Unaffected: 6.1.46 , ≤ 6.1.* (semver) Unaffected: 6.4.11 , ≤ 6.4.* (semver) Unaffected: 6.5 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/mptcp/protocol.h",
            "net/mptcp/subflow.c"
          ],
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix disconnect vs accept race\n\nDespite commit 0ad529d9fd2b (\"mptcp: fix possible divide by zero in\nrecvmsg()\"), the mptcp protocol is still prone to a race between\ndisconnect() (or shutdown) and accept.\n\nThe root cause is that the mentioned commit checks the msk-level\nflag, but mptcp_stream_accept() does acquire the msk-level lock,\nas it can rely directly on the first subflow lock.\n\nAs reported by Christoph than can lead to a race where an msk\nsocket is accepted after that mptcp_subflow_queue_clean() releases\nthe listener socket lock and just before it takes destructive\nactions leading to the following splat:\n\nBUG: kernel NULL pointer dereference, address: 0000000000000012\nPGD 5a4ca067 P4D 5a4ca067 PUD 37d4c067 PMD 0\nOops: 0000 [#1] PREEMPT SMP\nCPU: 2 PID: 10955 Comm: syz-executor.5 Not tainted 6.5.0-rc1-gdc7b257ee5dd #37\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014\nRIP: 0010:mptcp_stream_accept+0x1ee/0x2f0 include/net/inet_sock.h:330\nCode: 0a 09 00 48 8b 1b 4c 39 e3 74 07 e8 bc 7c 7f fe eb a1 e8 b5 7c 7f fe 4c 8b 6c 24 08 eb 05 e8 a9 7c 7f fe 49 8b 85 d8 09 00 00 \u003c0f\u003e b6 40 12 88 44 24 07 0f b6 6c 24 07 bf 07 00 00 00 89 ee e8 89\nRSP: 0018:ffffc90000d07dc0 EFLAGS: 00010293\nRAX: 0000000000000000 RBX: ffff888037e8d020 RCX: ffff88803b093300\nRDX: 0000000000000000 RSI: ffffffff833822c5 RDI: ffffffff8333896a\nRBP: 0000607f82031520 R08: ffff88803b093300 R09: 0000000000000000\nR10: 0000000000000000 R11: 0000000000003e83 R12: ffff888037e8d020\nR13: ffff888037e8c680 R14: ffff888009af7900 R15: ffff888009af6880\nFS:  00007fc26d708640(0000) GS:ffff88807dd00000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000000000000012 CR3: 0000000066bc5001 CR4: 0000000000370ee0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nCall Trace:\n \u003cTASK\u003e\n do_accept+0x1ae/0x260 net/socket.c:1872\n __sys_accept4+0x9b/0x110 net/socket.c:1913\n __do_sys_accept4 net/socket.c:1954 [inline]\n __se_sys_accept4 net/socket.c:1951 [inline]\n __x64_sys_accept4+0x20/0x30 net/socket.c:1951\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x47/0xa0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x6e/0xd8\n\nAddress the issue by temporary removing the pending request socket\nfrom the accept queue, so that racing accept() can\u0027t touch them.\n\nAfter depleting the msk - the ssk still exists, as plain TCP sockets,\nre-insert them into the accept queue, so that later inet_csk_listen_stop()\nwill complete the tcp socket disposal."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The race is between two local syscalls on the same MPTCP listening socket \u2014 `accept()` versus `close()`/`connect(AF_UNSPEC)`/shutdown \u2014 driven from the local process; a remote peer only supplies the pending connections and cannot itself schedule the disconnect.\nAC:L - The attacker controls both sides of the race with its own threads and can retry indefinitely over loopback, widening the window by queueing many unaccepted MPTCP connections; syzkaller reproduced it, so no attacker-uncontrollable precondition exists.\nPR:L - Only an unprivileged local user account is needed \u2014 creating `IPPROTO_MPTCP` sockets and calling listen/accept/close involves no capability check, and `net.mptcp.enabled` defaults to 1 including in a user-namespace-created netns (`unshare -Urn`).\nUI:N - The attacking process performs every step itself \u2014 creating the listener, generating connections, and racing accept against disconnect; no victim action is involved.\nS:U - The corrupted objects (`struct mptcp_sock`, subflow context) and the impact remain within the kernel\u0027s own security authority, with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - `mptcp_accept()` retains `subflow-\u003econn` without a reference while `mptcp_subflow_queue_clean()` destroys and frees the msk and `kfree_rcu()`s the subflow context, so the accept path reads freed heap memory (`msk-\u003efirst`, `msk-\u003econn_list`, `subflow-\u003etcp_sock`) \u2014 a use-after-free read that can be groomed into disclosing reclaimed kernel data.\nI:H - The racing `accept()` writes into the freed msk \u2014 `lock_sock()` on the freed socket lock, `sock_graft()` setting `sk_socket`/`sk_wq`, and `msk-\u003ein_accept_queue = 0` \u2014 giving controlled writes into reclaimed slab memory that are leverageable for control-flow hijack via heap spraying.\nA:H - The bug reproduces as an immediate kernel NULL-pointer dereference oops in `mptcp_stream_accept()` (`CR2=0000000000000012`), and the underlying use-after-free causes further panics; any local user can trigger it repeatedly to take down the system."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T09:14:22.176Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ded9f5551ce5cafa3c41c794428c27a0d0a00542"
        },
        {
          "url": "https://git.kernel.org/stable/c/b2b4c84eb7149f34c0f25f17042d095ba5357d68"
        },
        {
          "url": "https://git.kernel.org/stable/c/511b90e39250135a7f900f1c3afbce25543018a2"
        }
      ],
      "title": "mptcp: fix disconnect vs accept race",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2023-53490",
    "datePublished": "2025-10-01T11:45:42.182Z",
    "dateReserved": "2025-10-01T11:39:39.403Z",
    "dateUpdated": "2026-08-05T09:14:22.176Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

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