CVE-2026-64518: Linux kernel · tcp: Fix out-of-bounds access for twsk in tcp_ao_established_key().
Affects Linux kernelSource GCVE Database
Not known to be exploited · fixed in 6.8.0-1064.67~22.04.1 : update Linux kernel when convenient.
Data as of 6 Nov 2026, 17:26 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- Patch
- Available – fixed in 6.8.0-1064.67~22.04.1, 6.8.0-1067.75~22.04.1, 6.8.0-1065.72~22.04.1 +42
Exploitation evidence
Disclosed: evidence found.
CVE published 25 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 6 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- ubuntu.com/security/notices/USN-8618-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8663-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8664-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8729-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8761-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8729-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8761-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8781-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8729-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8761-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8802-1 (opens in a new tab)
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 patch 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 their Linux kernel to these fixed versions or newer to remediate this vulnerability. No additional mitigation steps are indicated by the vendor advisory.
Description
CVE-2026-64518 is a vulnerability in the Linux kernel involving an out-of-bounds access for the twsk structure in the tcp_ao_established_key() function. The issue arises because lockdep_sock_is_held() was added in tcp_ao_established_key() but can be called with a tcp_timewait_sock (twsk) that lacks the required sk_lock, causing out-of-bounds access. This flaw has been fixed by avoiding the use of lockdep_sock_is_held() for TCP_TIME_WAIT sockets.
References
- ubuntu.com/security/CVE-2026-64518 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-64518 (opens in a new tab)
- git.kernel.org/linus/03cb001ef87b3f8d859cf7f96329acf3d6235d29 (opens in a new tab)
- git.kernel.org/stable/c/03cb001ef87b3f8d859cf7f96329acf3d6235d29 (opens in a new tab)
- git.kernel.org/stable/c/29cf64d128c94cf98d1c69d8b2962d39db5ff4c6 (opens in a new tab)
- git.kernel.org/stable/c/510db031ba6eb40134f84c90ef963ea4b6dfb878 (opens in a new tab)
- git.kernel.org/stable/c/87bb3e719042f0030a6dad39118c6a6b2a491ad9 (opens in a new tab)
- ubuntu.com/security/notices/USN-8618-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8663-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8664-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8729-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8761-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8729-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8761-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8781-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8729-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8761-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8802-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-2 (opens in a new tab)