CVE-2026-64088: Linux kernel · batman-adv: tt: fix negative tt_buff_len
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.8 High · patch available : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 20% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 20 Jul 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
AI-suggested
A patch is available and should be applied by updating the Linux kernel to versions at or beyond the fixed releases. Ubuntu security advisories USN-8575-1 and USN-8576-1 provide updated kernel packages that address this and other vulnerabilities. After updating, a system reboot is required. Note that due to an ABI change, third-party kernel modules must be recompiled and reinstalled. Follow vendor instructions carefully to ensure full remediation.
Description
A vulnerability in the Linux kernel's batman-adv subsystem was fixed, addressing an issue where a signed 16-bit field (tt_buff_len) could wrap to a negative value due to improper type usage. This caused uninitialized memory to be used in buffer allocation, potentially leading to security issues. The flaw has been resolved in updated Linux kernel versions. The vulnerability has a high CVSS score of 8.8, indicating significant confidentiality, integrity, and availability impacts. Multiple Linux kernel versions prior to specific 5.15.x updates are affected. A patch is available and should be applied to mitigate the risk.
References
- nvd.nist.gov/vuln/detail/CVE-2026-64088 (opens in a new tab)
- git.kernel.org/stable/c/32edd2a28e112064020a2f319a8cb8a9e5a09767 (opens in a new tab)
- git.kernel.org/stable/c/33e5ede7ce6d92e531920d4bbd6d3e18ef1c6430 (opens in a new tab)
- git.kernel.org/stable/c/3c96dff00998314983b68a3e7caac07a66ebe496 (opens in a new tab)
- git.kernel.org/stable/c/4c4c2f340f4c27373bfcac8dc5032ce7bb474e47 (opens in a new tab)
- git.kernel.org/stable/c/4dab98961426d0cf6a1599cda6950b7596ca2fcd (opens in a new tab)
- git.kernel.org/stable/c/730de8733dd90f70d7580a9b329b971f8e1474a2 (opens in a new tab)
- git.kernel.org/stable/c/b64963a2ceeb7529310b6cf253a1e540784422f4 (opens in a new tab)
- git.kernel.org/stable/c/ed28ead3420c373a7928622f114bc6168075d1e1 (opens in a new tab)
- ubuntu.com/security/CVE-2026-64088 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-64088 (opens in a new tab)
- git.kernel.org/linus/b64963a2ceeb7529310b6cf253a1e540784422f4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8593-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8603-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8610-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8618-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8620-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8620-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8620-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8620-4 (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-8668-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)