RUSTSEC-2026-0401
Out-of-bounds read in `train_from_buffer` when sample sizes overflow
- 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
ZDICT_trainFromBuffer is never told the length of the samples buffer, so
train_from_buffer checked that the sample sizes add up to it. With
overflow checks off, as in release builds, that sum wrapped around: sizes
totalling 2^64 plus the buffer length passed the check, and the trainer read
past the end of the buffer. zstd::dict::from_continuous relies on this
check from zstd 0.4.10; older versions of zstd had their own, covered by a
separate advisory.
This requires the sample sizes to come from an untrusted source. The flaw was corrected by summing the sizes with overflow checks.
Affected versions
crates.io
| Package | Vulnerable | Fixed in |
|---|---|---|
| zstd-safe | >= 0.0.0-0, < 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-2026-0400 Use-after-free of a dictionary after a one-shot call on a context with an open stream | 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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