Vulnerability-Lookup

GHSA-M92Q-543G-VQ9X

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33

Details

In the Linux kernel, the following vulnerability has been resolved:

selinux: check connect-related permissions on TCP Fast Open

Similar to Landlock, SELinux was not updated when TCP Fast Open support was introduced to ensure connect-related permissions are checked when using TCP Fast Open. Update its socket_sendmsg() hook to call selinux_socket_connect() when MSG_FASTOPEN is passed.

Severity

8.4 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-72243"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:21:51Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nselinux: check connect-related permissions on TCP Fast Open\n\nSimilar to Landlock, SELinux was not updated when TCP Fast Open\nsupport was introduced to ensure connect-related permissions are\nchecked when using TCP Fast Open. Update its socket_sendmsg() hook to\ncall selinux_socket_connect() when MSG_FASTOPEN is passed.",
  "id": "GHSA-m92q-543g-vq9x",
  "modified": "2026-08-17T06:33:18Z",
  "published": "2026-08-15T06:32:17Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72243"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/11406d0d7e11b4e525bb2ace2c70107031d058da"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/44c74d27d1b9aaa99fa8a83640c1223575262b80"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/646ebbc5f2ff9147d084e1213143f091026a611c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d028bc080a0dcd6a7f8e1ae1bd32dda696505ba3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e507633bf76bccf1a6af27771fb0d6e2862b7eac"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fc633a598206d4f23af782db7c0b5f3a82751d2c"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-72243 (GCVE-0-2026-72243)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:54 – Updated: 2026-08-18 06:56

Title

selinux: check connect-related permissions on TCP Fast Open

Summary

In the Linux kernel, the following vulnerability has been resolved: selinux: check connect-related permissions on TCP Fast Open Similar to Landlock, SELinux was not updated when TCP Fast Open support was introduced to ensure connect-related permissions are checked when using TCP Fast Open. Update its socket_sendmsg() hook to call selinux_socket_connect() when MSG_FASTOPEN is passed.

Severity

8.4 (High)


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

Assigner

Linux mitre root

References

6 references

URL	Tags
https://git.kernel.org/stable/c/11406d0d7e11b4e52…
https://git.kernel.org/stable/c/e507633bf76bccf1a…
https://git.kernel.org/stable/c/d028bc080a0dcd6a7…
https://git.kernel.org/stable/c/fc633a598206d4f23…
https://git.kernel.org/stable/c/646ebbc5f2ff9147d…
https://git.kernel.org/stable/c/44c74d27d1b9aaa99…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: cf60af03ca4e71134206809ea892e49b92a88896 , < 11406d0d7e11b4e525bb2ace2c70107031d058da (git) Affected: cf60af03ca4e71134206809ea892e49b92a88896 , < e507633bf76bccf1a6af27771fb0d6e2862b7eac (git) Affected: cf60af03ca4e71134206809ea892e49b92a88896 , < d028bc080a0dcd6a7f8e1ae1bd32dda696505ba3 (git) Affected: cf60af03ca4e71134206809ea892e49b92a88896 , < fc633a598206d4f23af782db7c0b5f3a82751d2c (git) Affected: cf60af03ca4e71134206809ea892e49b92a88896 , < 646ebbc5f2ff9147d084e1213143f091026a611c (git) Affected: cf60af03ca4e71134206809ea892e49b92a88896 , < 44c74d27d1b9aaa99fa8a83640c1223575262b80 (git)
Linux	Linux	Affected: 3.6 Unaffected: 0 , < 3.6 (semver) Unaffected: 6.1.178 , ≤ 6.1.* (semver) Unaffected: 6.6.145 , ≤ 6.6.* (semver) Unaffected: 6.12.97 , ≤ 6.12.* (semver) Unaffected: 6.18.40 , ≤ 6.18.* (semver) Unaffected: 7.1.5 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "security/selinux/hooks.c"
          ],
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              "status": "affected",
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              "versionType": "git"
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            {
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              "status": "affected",
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              "versionType": "git"
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              "versionType": "git"
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              "version": "3.6"
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
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            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "versionStartIncluding": "3.6",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "3.6",
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nselinux: check connect-related permissions on TCP Fast Open\n\nSimilar to Landlock, SELinux was not updated when TCP Fast Open\nsupport was introduced to ensure connect-related permissions are\nchecked when using TCP Fast Open. Update its socket_sendmsg() hook to\ncall selinux_socket_connect() when MSG_FASTOPEN is passed."
        }
      ],
      "metrics": [
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            "baseScore": 8.4,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N",
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              "value": "AV:L - Exploitation requires a confined local process to invoke sendmsg(2)/sendto(2) with MSG_FASTOPEN; the vulnerable selinux_socket_sendmsg() LSM hook runs on the syscall path before TCP fast-open performs its implicit connect.\nAC:L - A confined task with SOCKET__WRITE can reliably trigger the bypass with one sendmsg/sendto using MSG_FASTOPEN and a destination address; TFO client is enabled by default (sysctl_tcp_fastopen=TFO_CLIENT_ENABLE) and no race or special victim state is needed.\nPR:L - The attacker must be an unprivileged process in a SELinux domain that grants socket write but denies connect/name_connect (e.g., confined Android apps, container workloads, hardened service domains); no real root or init-namespace privileges are required.\nUI:N - No victim interaction is required; the confined attacker process directly issues the bypassing syscall without needing another user or administrator to perform any action.\nS:C - Successful exploitation crosses the SELinux MAC confinement boundary, allowing a sandboxed domain to establish outbound TCP/MPTCP connections that connect(2) and name_connect policy would have blocked, escaping the intended network policy scope.\nC:H - Bypassing connect and name_connect mediation lets a confined process open TCP/MPTCP sessions to SELinux-forbidden destinations and read arbitrary response data from those services (internal APIs, metadata endpoints, databases), constituting unauthorized information disclosure.\nI:H - The bypass enables unauthorized outbound connection establishment and transmission of arbitrary application data (including SYN-cookie payload) to hosts and ports explicitly denied by SELinux connect/name_connect rules, violating integrity of the confinement policy.\nA:N - This is a pure SELinux LSM policy-bypass flaw with no kernel memory corruption, panic, oops, hang, or resource exhaustion; exploitation does not impact system availability."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-18T06:56:32.099Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        {
          "url": "https://git.kernel.org/stable/c/44c74d27d1b9aaa99fa8a83640c1223575262b80"
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      "title": "selinux: check connect-related permissions on TCP Fast Open",
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    "cveId": "CVE-2026-72243",
    "datePublished": "2026-08-15T05:54:31.117Z",
    "dateReserved": "2026-08-09T03:40:39.914Z",
    "dateUpdated": "2026-08-18T06:56:32.099Z",
    "state": "PUBLISHED"
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}

Sightings

Author	Source	Type	Date	Other

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

GHSA-M92Q-543G-VQ9X

CVE-2026-72243 (GCVE-0-2026-72243)

Tags

Sightings

Nomenclature