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Advisory record · RUSTSEC-2026-0256

Panic-safety unsoundness in `truncate_back`, `truncate_front`, `clear`, and `extend_from_slice` (use-after-free / double-free)

No CVSS score

Published by OSV at 11 Aug 2026, 12:00 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
circular-buffercrates.io>=0.0.0-0, <2.0.12.0.1
Identifiers
RUSTSEC-2026-0256
Published
11 Aug 2026
Updated
12 Aug 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

The circular-buffer crate before 2.0.1 is affected. Several methods (truncate_back, truncate_front, clear, extend_from_slice) drop elements before updating the buffer's metadata, so if an element's Drop panics, the buffer still treats already-dropped elements as live, leading to double-free or use-after-free. The source says this is reachable from safe Rust using catch_unwind with element types whose Drop can panic. Upgrade to circular-buffer 2.0.1, which fixes the ordering.

Written 8 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

No source has published a CVSS score for this record yet.

  • CISA KEV Not listed.
  • EPSS No score.

Timeline

  1. 31 Oct 2026, 15:18 UTC First seen by agentprime
  2. 31 Oct 2026, 15:18 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.