CVE-2026-72243

SELinux network-policy bypass via TCP Fast Open

Published Aug 15, 2026 · Updated Aug 15, 2026

Improper access control in affected Linux kernels allows local users to bypass SELinux TCP connect policy through TCP Fast Open. The SELinux socket_sendmsg hook checks only socket write permission for MSG_FASTOPEN, letting sendmsg reach connect semantics without selinux_socket_connect. A local process confined by an SELinux domain that denies the destination can establish an outbound TCP or MPTCP connection without the expected connect, name_connect, or NetLabel checks.

CVSS severity7.0
High
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in affected Linux kernels allows local users to bypass SELinux TCP connect policy through TCP Fast Open. The SELinux socket_sendmsg hook checks only socket write permission for MSG_FASTOPEN, letting sendmsg reach connect semantics without selinux_socket_connect. A local process confined by an SELinux domain that denies the destination can establish an outbound TCP or MPTCP connection without the expected connect, name_connect, or NetLabel checks.

The record

CVE
CVE-2026-72243
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1562.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <6.1.178
  2. Affected versionversion=0 <6.12.97
  3. Affected versionversion=0 <6.18.40
  4. Affected versionversion=0 <6.6.145
  5. Affected versionversion=0 <7.1.5
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <11406d0d7e11b4e525bb2ace2c70107031d058da
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <44c74d27d1b9aaa99fa8a83640c1223575262b80
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <646ebbc5f2ff9147d084e1213143f091026a611c
  9. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d028bc080a0dcd6a7f8e1ae1bd32dda696505ba3
  10. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e507633bf76bccf1a6af27771fb0d6e2862b7eac
  11. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fc633a598206d4f23af782db7c0b5f3a82751d2c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0 <6.1.178; version=0 <6.12.97; version=0 <6.18.40; version=0 <6.6.145; version=0 <7.1.5; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <11406d0d7e11b4e525bb2ace2c70107031d058da; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <44c74d27d1b9aaa99fa8a83640c1223575262b80; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <646ebbc5f2ff9147d084e1213143f091026a611c; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d028bc080a0dcd6a7f8e1ae1bd32dda696505ba3; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e507633bf76bccf1a6af27771fb0d6e2862b7eac; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fc633a598206d4f23af782db7c0b5f3a82751d2c

Published CVSS scores

7.0OracleCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1562.001Impair Defenses: Disable or Modify Tools

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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