CVE-2026-53236: Linux kernel · tcp: restrict SO_ATTACH_FILTER to priv users
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 6.8.0-1066.69~22.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1066.69~22.04.1, 6.8.0-1070.78~22.04.1, 6.8.0-1068.75~22.04.1 +38
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jun 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
A fix is available and has been released in Linux kernel versions 6.8.0-1064.67~22.04.1 and later. Users and administrators should update affected Linux kernel versions to these fixed releases or later to mitigate this vulnerability. No additional mitigation is required beyond applying the official patch.
Description
A vulnerability in the Linux kernel allowed unprivileged users to attach a Berkeley Packet Filter (cBPF) to TCP sockets via SO_ATTACH_FILTER, potentially enabling a side-channel attack to leak TCP sequence and acknowledgment numbers. The vulnerability has been fixed by restricting this capability to users with CAP_NET_ADMIN privileges. Multiple Linux kernel versions are affected, with fixes available in later kernel releases.
References
- ubuntu.com/security/CVE-2026-53236 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-53236 (opens in a new tab)
- git.kernel.org/linus/5d39580f68e6ddeedd15e587282207489dfb3da2 (opens in a new tab)
- git.kernel.org/stable/c/3747de241a66ef2c7032d2cc2b826a47c5fa0f6a (opens in a new tab)
- git.kernel.org/stable/c/5d39580f68e6ddeedd15e587282207489dfb3da2 (opens in a new tab)
- git.kernel.org/stable/c/82b3e7ce10c53fc12aab8904745603efc74f8c07 (opens in a new tab)
- git.kernel.org/stable/c/c68517a3e18e20997808821c5559d0cba4d776c1 (opens in a new tab)
- git.kernel.org/stable/c/ecfe9171b26ae3eed0cd8bab7a943e9e2c9e51ba (opens in a new tab)
- git.kernel.org/stable/c/ede69b8f6670600e534591664584f810d7c385f9 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8727-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-53236 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8800-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-3 (opens in a new tab)