CVE-2026-72243: Linux kernel · selinux: check connect-related permissions on TCP Fast Open
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.4 High · fixed in 7.0.0-1014.14~24.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 7.0.0-1014.14~24.04.1, 7.0.0-1017.17~24.04.1, 7.0.0-1016.16~24.04.1 +12
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 15 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
An official patch is available to fix this vulnerability by updating SELinux to properly check connect permissions when TCP Fast Open is used. Users should apply the vendor-provided updates for the affected Linux kernel versions promptly. No additional mitigations are specifically recommended beyond applying the patch.
Description
A vulnerability in the Linux kernel SELinux implementation was resolved that involved missing checks for connect-related permissions when using TCP Fast Open. The issue was that SELinux's socket_sendmsg() hook did not call selinux_socket_connect() when the MSG_FASTOPEN flag was used, potentially allowing unauthorized TCP connections. This flaw has been fixed by updating the SELinux hook to properly enforce connect permissions with TCP Fast Open. The vulnerability affects specific Linux kernel versions and has a CVSS score of 8.4, indicating high impact on confidentiality and integrity. A patch is available to address this issue.
References
- nvd.nist.gov/vuln/detail/CVE-2026-72243 (opens in a new tab)
- git.kernel.org/stable/c/11406d0d7e11b4e525bb2ace2c70107031d058da (opens in a new tab)
- git.kernel.org/stable/c/44c74d27d1b9aaa99fa8a83640c1223575262b80 (opens in a new tab)
- git.kernel.org/stable/c/646ebbc5f2ff9147d084e1213143f091026a611c (opens in a new tab)
- git.kernel.org/stable/c/d028bc080a0dcd6a7f8e1ae1bd32dda696505ba3 (opens in a new tab)
- git.kernel.org/stable/c/e507633bf76bccf1a6af27771fb0d6e2862b7eac (opens in a new tab)
- git.kernel.org/stable/c/fc633a598206d4f23af782db7c0b5f3a82751d2c (opens in a new tab)
- ubuntu.com/security/CVE-2026-72243 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-72243 (opens in a new tab)
- git.kernel.org/linus/44c74d27d1b9aaa99fa8a83640c1223575262b80 (opens in a new tab)
- ubuntu.com/security/notices/USN-8888-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8889-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8886-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8888-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-3 (opens in a new tab)