CVE-2026-45971: bpf: Limit bpf program signature size

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-27 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Limit bpf program signature size Practical BPF signatures are significantly smaller than KMALLOC_MAX_CACHE_SIZE Allowing larger sizes opens the door for abuse by passing excessive size values and forcing the kernel into expensive allocation paths (via kmalloc_large or vmalloc).

Affected products

Linux kernel: from 6.18 before 6.18.14; from 6.19 before 6.19.4 — fixed in 6.18.14, 6.19.4

How to fix

Upgrade to a fixed version: Linux kernel 6.18.14, 6.19.4. Check the vendor advisory for mitigations.

References

https://git.kernel.org/stable/c/5835a077c6f5c565d525eaca9fac01572b97a9b9
https://git.kernel.org/stable/c/ea1535e28bb3773fc0b3cbd1f3842b808016990c
https://git.kernel.org/stable/c/eb8166c79097996396468a341de258a798789d36

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