RUSTSEC-2026-0400
Use-after-free of a dictionary after a one-shot call on a context with an open stream
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.
What each source reports
OSV No score
Use-after-free of a dictionary after a one-shot call on a context with an open stream
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.
- Record
RUSTSEC-2026-0400- Updated
- 2026-11-02
Affected packages
| Package | Affected | Fixed |
|---|---|---|
zstd-safecrates.io |
3.0.1 up to 7.4.0, 8.0.0-0 up to 8.2.0 | 7.4.08.2.0 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
RUSTSEC-2026-0400 is a vulnerability with no CVSS score yet in zstd-safe, published October 16, 2026. No source lists public exploit code. Fixed in zstd-safe 7.4.0.