CVE-2026-72243 (GCVE-0-2026-72243)
Vulnerability from cvelistv5 – Published: 2026-08-15 05:54 – Updated: 2026-08-18 06:56
VLAI
EPSS
VEX
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)
Assigner
References
6 references
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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"status": "unaffected",
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}
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}
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"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."
}
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"version": "3.1"
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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."
}
]
}
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{
"url": "https://git.kernel.org/stable/c/44c74d27d1b9aaa99fa8a83640c1223575262b80"
}
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"datePublished": "2026-08-15T05:54:31.117Z",
"dateReserved": "2026-08-09T03:40:39.914Z",
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}
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"id": "CVE-2026-72243",
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"product_status:known_not_affected": "14",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: selinux: check connect-related permissions on TCP Fast Open",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72243.json",
"version": "3"
},
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"current_release_date": "2026-10-08T23:50:17Z",
"cve": "CVE-2026-72243",
"id": "CVE-2026-72243",
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"status": "interim",
"title": "SUSE CVE CVE-2026-72243",
"url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-72243.json",
"version": "6"
}
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
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
| 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.
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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.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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