CVE-2025-21728: bpf: Send signals asynchronously if !preemptible

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: 2025-02-27 · updated 2026-10-15

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Send signals asynchronously if !preemptible BPF programs can execute in all kinds of contexts and when a program running in a non-preemptible context uses the bpf_send_signal() kfunc, it will cause issues because this kfunc can sleep. Change `irqs_disabled()` to `!preemptible()`.

Affected products

Linux kernel: from 5.4.33 before 5.4.291; from 5.5.18 before 5.6; from 5.6.1 before 5.10.235; from 5.11 before 5.15.179; from 5.16 before 6.1.129; from 6.2 before 6.6.76 — fixed in 5.10.235, 5.15.179, 5.4.291, 5.6, 6.1.129, 6.12.13

How to fix

Upgrade to a fixed version: Linux kernel 5.10.235, 5.15.179, 5.4.291, 5.6. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2025-21728 or the next vulnerability affects your stack