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=7.2.2,fixed=8.2.0; Gyscos Zstd-Safe 7.2.2 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 over the network.

Check whether you run zstd-safe (crates.io) or Gyscos 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.

zstd-safe Seekable decompress buffer overrun on invalid offset

Severity: info · Published 2026-10-16

The zstd-safe Rust library, which provides compression and decompression functionality, contains a flaw in its seekable decompression feature. When processing archives with offsets past the end of the data, the library incorrectly sets a buffer's length to a value exceeding its capacity, allowing attackers to read adjacent heap memory or cause memory corruption. Applications using the seekable feature with untrusted archives face heap information disclosure and potential denial of service.

Technologies: zstd-safe (crates.io), Gyscos Zstd-Safe. Vendors: crates.io, Gyscos.

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=7.2.2,fixed=8.2.0; Gyscos Zstd-Safe 7.2.2 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 over the network.
Am I affected?: Check whether you run zstd-safe (crates.io) or Gyscos 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 exists in `Seekable::decompress` and `AdvancedSeekable::decompress` functions (versions 7.2.2 to 8.1.x). The underlying C function `ZSTD_seekable_decompress` returns a wrapped-around length when given an offset past the end of the data, which the Rust wrapper incorrectly passes to `Vec::set_len` without validating against buffer capacity. This causes heap memory disclosure on read and corruption on append; additionally, offsets near `u64::MAX` can cause the call to hang. The fix validates all counts against buffer capacity and clamps requests to the end of the data.

Affected products

gyscos zstd-safe 7.2.2 to 8.1.x

Timeline

2026-10-16: disclosed
2026-10-26: patched

References

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