CVE-2026-6654 Use-After-Free and Double-Free in IntoIter::drop when element drop panics
A use-after-free and double-free vulnerability in the thin_vec crate allows attackers to execute arbitrary code or cause denial of service when element drop panics.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-6654?
CVE-2026-6654 is a medium-severity use after free vulnerability in Mozilla thin-vec, published on 20 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Double-Free / Use-After-Free (UAF) in the `IntoIter::drop` and `ThinVec::clear` functions in the thin_vec crate. A panic in `ptr::drop_in_place` skips setting the length to zero.
Which versions are affected by CVE-2026-6654?
3 open source packages ship an affected version, including thin-vec. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
thin-vec crates.io | All versions | 0.2.16 |
thin-vec crates.io | All versions | 0.2.16 |
thin-vec crates.io | From 0.0.0-0 | 0.2.16 |
Products include Mozilla Thin-Vec.
How do I fix CVE-2026-6654?
Upgrade thin-vec to 0.2.16 or later.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-6654 being exploited?
There is no known exploitation of CVE-2026-6654 in the wild and no public exploit code.
Sources
Also known as CLEANSTART-2026-GX06770, DEBIAN-CVE-2026-6654, GHSA-xphw-cqx3-667j, RUSTSEC-2026-0103, UBUNTU-CVE-2026-6654.