RUSTSEC-2024-0363: Binary Protocol Misinterpretation caused by Truncating or Overflowing Casts

What to do

1. See which version you have: cargo tree -i sqlx (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p sqlx. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example sqlx = "0.8.1") 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

The following presentation at this year's DEF CON was brought to our attention on the SQLx Discord:

> SQL Injection isn't Dead: Smuggling Queries at the Protocol Level > <http://web.archive.org/web/20240812130923/https://media.defcon.org/DEF%20CON%2032/DEF%20CON%2032%20presentations/DEF%20CON%2032%20-%20Paul%20Gerste%20-%20SQL%20Injection%20Isn't%20Dead%20Smuggling%20Queries%20at%20the%20Protocol%20Level.pdf> > (Archive link for posterity.)

Essentially, encoding a value larger than 4GiB can cause the length prefix in the protocol to overflow, causing the server to interpret the rest of the string as binary protocol commands or other data.

It appears SQLx _does_ perform truncating casts in a way that could be problematic, for example: <https://github.com/launchbadge/sqlx/blob/6f2905695b9606b5f51b40ce10af63ac9e696bb8/sqlx-postgres/src/arguments.rs#L163>

This code has existed essentially since the beginning, so it is reasonable to assume that all published versions <= 0.8.0 are affected.

Mitigation

As always, you should make sure your application is validating untrustworthy user input. Reject any input over 4 GiB, or any input that could _encode_ to a string longer than 4 GiB. Dynamically built queries are also potentially problematic if it pushes the message size over this 4 GiB bound.

Encode::size_hint() can be used for sanity checks, but do not assume that the size returned is accurate. For example, the Json<T> and Text<T> adapters have no reasonable way to predict or estimate the final encoded size, so they just return size_of::<T>() instead.

For web application backends, consider adding some middleware that limits the size of request bodies by default.

Resolution

sqlx 0.8.1 has been released with the fix: <https://github.com/launchbadge/sqlx/blob/main/CHANGELOG.md#081---2024-08-23>

Postgres users are advised to upgrade ASAP as a possible exploit has been demonstrated: <https://github.com/launchbadge/sqlx/issues/3440#issuecomment-2307956901>

MySQL and SQLite do not _appear_ to be exploitable, but upgrading is recommended nonetheless.

References

• Package: crates.io/crates/sqlx
• Advisory: rustsec.org/advisories/RUSTSEC-2024-0363.html
• Report: github.com/launchbadge/sqlx/issues/3440

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