RUSTSEC-2026-0400
Use-after-free of a dictionary after a one-shot call on a context with an open stream
- Severity
- Not rated yet
- No source has published a CVSS score yet
- Exploit chance (EPSS)
- —
- No score published
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- —
- Not classified
- Fix
8.2.0- Upgrade zstd-safe to this version or later
Description
The one-shot DCtx and CCtx methods assumed the C library resets the
context, but it leaves an open stream as it is. When a stream was left
unfinished on a context, a one-shot call such as decompress_using_dict
could leave the context pointing at the dictionary borrowed for that call,
and the next streaming call resumed the stream against it after it was
freed: decompressed output then contained freed heap memory. On the
compression side, the stream resumed against the one-shot call's buffers.
This requires an application to use one context for both streaming and one-shot calls without a reset in between. The flaw was corrected by resetting the session after one-shot calls whenever a stream may be open.
Affected versions
crates.io
| Package | Vulnerable | Fixed in |
|---|---|---|
| zstd-safe | >= 3.0.1, < 8.2.0 |
8.2.0 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
zstd-safe crates.io → 8.2.0
- cargo
cargo update -p zstd-safe --precise 8.2.0
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| RUSTSEC-2026-0406 Use-after-free when changing a multithreaded context with an unfinished frame | Not rated yet | Also affects zstd-safe |
| RUSTSEC-2026-0405 Out-of-bounds read with an out-of-range `InBuffer::pos` | Not rated yet | Also affects zstd-safe |
| RUSTSEC-2026-0404 Double free in `DCtx::try_clone` | Not rated yet | Also affects zstd-safe |
| RUSTSEC-2026-0403 Uninitialized memory exposed when streaming decompression of a legacy frame fails | Not rated yet | Also affects zstd-safe |
| RUSTSEC-2026-0402 Heap buffer overflow in `CCtx::try_clone` on a multithreaded context | Not rated yet | Also affects zstd-safe |
| RUSTSEC-2026-0401 Out-of-bounds read in `train_from_buffer` when sample sizes overflow | Not rated yet | Also affects zstd-safe |
| RUSTSEC-2026-0399 Use-after-free through `init_using_cdict` and `init_using_ddict` | Not rated yet | Also affects zstd-safe |
| RUSTSEC-2026-0398 `Seekable::decompress` sets a `Vec` length beyond its capacity for offsets past the end | Not rated yet | Also affects zstd-safe |
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