Reported

August 24, 2026

Issued

August 24, 2026

Package

stable-vec (crates.io)

Type

INFO Unsound

Categories

• memory-corruption

Keywords

#panic-safety #memory-safety #use-after-free #double-free

Aliases

• GHSA-mr2v-63pc-gmr4

References

• https://github.com/LukasKalbertodt/stable-vec/pull/51

Patched

• >=0.4.3

Affected Functions

Version

stable_vec::BitVecCore::clear

• <0.4.3

Description

BitVecCore::clear drops every occupied element with drop_in_place and only afterwards clears the occupancy bits and resets len. If an element's Drop panics, those metadata updates are skipped, so the slot of the already-dropped element stays marked as occupied. BitVecCore::drop calls clear() again, visits the same slot, and drops the element a second time — a double-free / use-after-free reachable from safe Rust.

Reachable via the public StableVec::clear and ExternStableVec::clear, which delegate to BitVecCore::clear.

Impact

• CWE-415 (Double Free): the same allocation is freed twice.
• CWE-416 (Use-After-Free): a freed allocation is accessed during a repeated Drop.

Reachable entirely from safe Rust via catch_unwind with element types whose Drop can panic. Confirmed under AddressSanitizer on 0.4.2.

Fix

Fixed in stable-vec 0.4.3 by removing each element via remove_at, which clears the occupancy bit before taking the value out.

Release 0.4.3 also fixes several other panic-safety issues found by the maintainer; see GHSA-mr2v-63pc-gmr4 and the 0.4.3 changelog for the full list.

Advisory available under CC0-1.0 license.