RUSTSEC-2026-0238: Low-level GCM ignores the operation nonce

What to do

1. See which version you have: cargo tree -i dcrypt-algorithms (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p dcrypt-algorithms. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example dcrypt-algorithms = "2.0.0") 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

In all published versions of dcrypt-algorithms before 2.0.0, the low-level Gcm builder required an operation nonce but derived J0 from the nonce captured by the original Gcm constructor. Multiple operations could therefore silently reuse a nonce even when callers supplied distinct values, compromising confidentiality and authenticity under an affected key.

Version 2.0.0 makes Gcm key-only and passes the operation nonce through IV derivation, encryption, and decryption. It also corrects non-96-bit IV processing, rejects tags shorter than 96 bits, and enforces counter limits. Applications must upgrade, identify affected keys, rotate them, and re-encrypt affected data; updating the implementation cannot restore security after nonce reuse.

References

• Package: crates.io/crates/dcrypt-algorithms
• Advisory: rustsec.org/advisories/RUSTSEC-2026-0238.html
• Web: github.com/ioi-foundation/dcrypt/commit/c99cc86f0ee353010cd202cbcd2c310371b0bbb8
• Web: github.com/ioi-foundation/dcrypt/commit/c99cc86f0ee353010cd202cbcd2c310371b0bbb8
• Web: github.com/ioi-foundation/dcrypt/releases/tag/v2.0.0

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