The Linux kernel vulnerability CVE-2026-64354 affects the BPF subsystem's handling of BTF repeated fields. Specifically, btf_parse_struct_metas() processes user-supplied BTF data during BPF_BTF_LOAD, and btf_repeat_fields() expands repeatable fields into a fixed-size scratch array. The calculation for remaining capacity uses a 32-bit unsigned integer, which can wrap around if the BTF is malformed, causing the capacity check to incorrectly pass. Consequently, memcpy() writes beyond the array boundary, leading to a potential buffer overflow. The fix involves using checked addition and multiplication to validate counts and rejecting impossible values before copying repeated fields.

Successful exploitation could result in a buffer overflow in kernel memory, potentially allowing local attackers with limited privileges to escalate privileges or cause denial of service by corrupting kernel memory. The CVSS vector indicates local attack vector with low complexity, no user interaction, and high impact on confidentiality, integrity, and availability.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since this is a Linux kernel vulnerability, monitor official Linux kernel and distribution vendor advisories (e.g., Ubuntu) for patches or updates addressing CVE-2026-64354. Apply official kernel updates once available to remediate the issue.