RUSTSEC-2026-0393 json
Out-of-bounds read when training a dictionary from inconsistent sample sizes
published 26d ago modified 16d ago
- cvss
- —
- not scored
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- —
- no score, EPSS covers CVEs only
- public exploits
- 0
- none known
Summary
`ZDICT_trainFromBuffer` is never told the length of the samples buffer. Before 0.4.10, `zstd::dict::from_continuous` (initially `train_dict`) called it directly: up to 0.2.1 without checking the sample sizes against the buffer at all, and from 0.3.0 with a sum that wraps around when overflow checks are off, as in release builds. Sizes that do not describe the buffer made the trainer read past its end.
This requires the sample sizes to come from an untrusted source. From 0.4.10, training goes through zstd-safe, where the same flaw is covered by the zstd-safe advisory for it, fixed in zstd-safe 8.2.0.
Patch / fix
- crates.io zstd 0.4.10
- github.com/gyscos/zstd-rs@781ea45 commit
- github.com/gyscos/zstd-rs#384 pull request
Is RUSTSEC-2026-0393 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerAffected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| crates.io | zstd | >=0.1.1, <0.4.10 |
0.4.10 |
References
Sources
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.