Panic-safety unsoundness in BitVecCore::clear (double-free / use-after-free)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

not scored

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

`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…

Published by the source

24 Aug 2026, 12:00 UTC

Last modified by the source

25 Aug 2026, 02:45 UTC

Source last checked

23 Oct 2026, 22:04 UTC

1. Revision 1 · created · 24 Oct 2026

   Published from osv record RUSTSEC-2026-0267

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# Patch Next advisory brief: GHSA-mr2v-63pc-gmr4

Advisory: Panic-safety unsoundness in `BitVecCore::clear` (double-free / use-after-free)
IDs: GHSA-mr2v-63pc-gmr4
Record: https://patchnext.com/advisories/rustsec-2026-0267 (revision 1, source checked 23 Oct 2026, 22:04 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: stable-vec 0.4.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io stable-vec: affected >= 0.0.0-0, < 0.4.3; fixed in 0.4.3

## Suggested inspection (read-only)
- crates.io stable-vec: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on stable-vec.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/RUSTSEC-2026-0267 (OSV record RUSTSEC-2026-0267 lists affected ranges: crates.io stable-vec >=0.0.0-0 <0.4.3 (fixed))

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