CVE-2026-64353: bpf: Keep dynamic inner array lookups nullable

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-25 · updated 2026-09-03

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Keep dynamic inner array lookups nullable An ARRAY_OF_MAPS can use an array created with BPF_F_INNER_MAP as its inner map template. A concrete inner array with a different max_entries value can then replace the template. After a successful outer map lookup, the verifier represents the resulting map pointer using the inner map template. Const-key lookup nullness elision consequently uses the template max_entries even though the runtime helper uses the concrete inner map max_entries. Do not elide lookup result nullness for maps marked with BPF_F_INNER_MAP, because the template max_entries does not prove that the key is in bounds for the concrete runtime map.

Affected products

Linux kernel: from 6.14 before 6.18.40; from 6.19 before 7.1.4 — fixed in 6.18.40, 7.1.4

How to fix

Upgrade to a fixed version: Linux kernel 6.18.40, 7.1.4. Check the vendor advisory for mitigations.

References

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