RUSTSEC-2025-0015: Denial of Service via malicious Web Push endpoint

What to do

1. See which version you have: cargo tree -i web-push (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p web-push. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example web-push = "0.10.3") or update the dependency that pulls it in.
3. Check again with cargo audit, or paste your Cargo.lock into our Cargo.toml checker.

Details from the advisory

Prior to version 0.10.3, the built-in clients of the web-push crate eagerly allocated memory based on the Content-Length header returned by the Web Push endpoint. Malicious Web Push endpoints could return a large Content-Length without ever having to send as much data, leading to denial of service by memory exhaustion.

Services providing Web Push notifications typically allow the user to register an arbitrary endpoint, so the endpoint should not be trusted.

The fixed version 0.10.3 now limits the amount of memory it will allocate for each response, limits the amount of data it will read from the endpoint, and returns an error if the endpoint sends too much data.

As before, it is recommended that services add a timeout for each request to Web Push endpoints.

References

• Package: crates.io/crates/web-push
• Advisory: rustsec.org/advisories/RUSTSEC-2025-0015.html
• Web: github.com/pimeys/rust-web-push/pull/68

From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.