RUSTSEC-2022-0055: No default limit put on request bodies

What to do

1. See which version you have: cargo tree -i axum-core (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p axum-core. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example axum-core = "0.3.0-rc.2") 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

<bytes::Bytes as axum_core::extract::FromRequest>::from_request would not, by default, set a limit for the size of the request body. That meant if a malicious peer would send a very large (or infinite) body your server might run out of memory and crash.

This also applies to these extractors which used Bytes::from_request internally:

• axum::extract::Form
• axum::extract::Json
• String

The fix is also in axum-core 0.3.0.rc.2 but 0.3.0.rc.1 _is_ vulnerable.

Because axum depends on axum-core it is vulnerable as well. The vulnerable versions of axum are <= 0.5.15 and 0.6.0.rc.1. axum >= 0.5.16 and >= 0.6.0.rc.2 does have the fix and are not vulnerable.

The patched versions will set a 2 MB limit by default.

References

• Package: crates.io/crates/axum-core
• Advisory: rustsec.org/advisories/RUSTSEC-2022-0055.html
• Web: github.com/tokio-rs/axum/pull/1346

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