CVE-2026-64354: Linux kernel · bpf: Validate BTF repeated field counts before expansion
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in ff77d013b737c0f77d925e2f2c59f0cf3d76bd35 : patch Linux kernel soon.
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.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in ff77d013b737c0f77d925e2f2c59f0cf3d76bd35, cd407de2ef5dc70f1970b343ffaa16186340fdfd, c5ff816d5f13900c3f1f3298cfcc61339e056e56 +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 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
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Validate BTF repeated field counts before expansion btf_parse_struct_metas() walks user-supplied BTF during BPF_BTF_LOAD, and btf_repeat_fields() expands repeatable fields from array elements into the fixed BTF_FIELDS_MAX scratch array used by btf_parse_fields(). The remaining-capacity check performs the expanded field count calculation in u32. A malformed BTF can wrap that calculation, causing the check to pass even when the expanded field count exceeds the scratch array capacity. The following memcpy() can then write past the end of the array. Use checked addition and multiplication before copying repeated fields and reject impossible counts.
References
- git.kernel.org/stable/c/c5ff816d5f13900c3f1f3298cfcc61339e056e56 (opens in a new tab)
- git.kernel.org/stable/c/cd407de2ef5dc70f1970b343ffaa16186340fdfd (opens in a new tab)
- git.kernel.org/stable/c/ff77d013b737c0f77d925e2f2c59f0cf3d76bd35 (opens in a new tab)
- git.kernel.org/stable/c/b9452b594fd3aecbfd4aa0a6a1f741330a37dab7 (opens in a new tab)