Quick answers
- Is This vulnerability exploited in the wild?
- No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
- How severe is This vulnerability?
- Informational severity, published 16 October 2026.
- Which products and versions are affected?
- zstd-safe (crates.io) SEMVER:introduced=3.0.1,fixed=8.2.0; Zstd-Rs Zstd-Safe 3.0.1 to 8.1.x.
- Is there a fix for This vulnerability?
- Yes. zstd-safe (crates.io): upgrade to 8.2.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is This vulnerability attacked?
- It is attacked with local access.
- Am I affected?
- Check whether you run zstd-safe (crates.io) or Zstd-Rs Zstd-Safe at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- zstd-safe (crates.io): upgrade to 8.2.0 or later
cargo update -p zstd-safe
Technical details
The vulnerability is a use-after-free in the DCtx decompression context when one-shot methods (decompress, decompress_using_dict, decompress_using_ddict) are called on a context with an open unfinished stream. The underlying C library does not reset the context state, leaving the stream active. A subsequent streaming call resumes against freed dictionary memory, exposing heap contents in decompressed output. This requires an application to interleave streaming and one-shot operations without explicit context resets.
Affected products
- zstd-rs zstd-safe 3.0.1 to 8.1.x
Timeline
- 2026-10-16: disclosed
- 2026-10-26: patched