RUSTSEC-2026-0002: `IterMut` violates Stacked Borrows by invalidating internal pointer

What to do

1. See which version you have: cargo tree -i lru (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p lru. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example lru = "0.16.3") 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

Affected versions of this crate contain a soundness issue in the IterMut iterator implementation. The IterMut::next and IterMut::next_back methods temporarily create an exclusive reference to the key when dereferencing the internal node pointer.

This invalidates the shared pointer held by the internal HashMap, violating Stacked Borrows rules.

References

• Package: crates.io/crates/lru
• Advisory: rustsec.org/advisories/RUSTSEC-2026-0002.html
• Web: github.com/jeromefroe/lru-rs/pull/224

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

Other advisories for lru

• VulnerabilityRUSTSEC-2021-0130 · 2021-12-21Use after free in lru crate
• UnsoundRUSTSEC-2026-0253 · 2026-05-12Potential use-after-free due to lack of panic safety in `LruCache::pop()`

Full security history of lru