CVE-2026-98376 bpf: Use array_map_meta_equal for percpu array inner map replacement
A local attacker with BPF privileges can trigger an out-of-bounds read in the Linux kernel by replacing a percpu array inner map, potentially leaking memory or causing a crash.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98376?
CVE-2026-98376 is a high-severity memory corruption vulnerability in Linux, published on 9 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
bpf: Use array_map_meta_equal for percpu array inner map replacement
percpu_array_map_ops.map_meta_equal points to the generic bpf_map_meta_equal(), which does not compare max_entries. When a percpu array serves as an inner map, replacing it with one that has fewer max_entries bypasses the check. Since percpu_array_map_gen_lookup() inlines the original template's index_mask as a JIT immediate, a lookup on the replacement map can access pptrs[] out of bounds.
Point percpu_array_map_ops.map_meta_equal to array_map_meta_equal(), which already enforces the max_entries equality check.
Add a selftest to verify that replacing a percpu array inner map with a differently-sized one is rejected.
Which versions are affected by CVE-2026-98376?
How do I fix CVE-2026-98376?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-98376 being exploited?
There is no known exploitation of CVE-2026-98376 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-98376, DEBIAN-CVE-2026-98376, GHSA-69ch-wm32-w5g8, UBUNTU-CVE-2026-98376.