RUSTSEC-2026-0397 `OutBuffer::around_pos` exposes uninitialized memory
Not scored
Published
Check this codebase for RUSTSEC-2026-0397 and fix it if it is affected.
What it is: RUSTSEC-2026-0397 is a vulnerability in zstd-safe, published on 16 Oct 2026.
Exploitation: There is no known exploitation of RUSTSEC-2026-0397 in the wild and no public exploit code.
Affected packages and fixed versions:
- zstd-safe (crates.io): affected from 4.0.0; fixed in 8.2.0
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/RUSTSEC-2026-0397/ (Markdown: https://insights.sbomify.com/RUSTSEC-2026-0397/index.md)
- Exploited in the wild
- Not known
- Fix
- Available
What is RUSTSEC-2026-0397?
RUSTSEC-2026-0397 is a vulnerability in zstd-safe, published on 16 Oct 2026.
Official description
OutBuffer::around_pos accepted a position past the initialized length of a
Vec<u8>. The next streaming call then marked everything before the
position as initialized, so safe code could read stale heap memory between
the vector's previous length and that position.
The flaw was corrected by zero-filling that gap.
Which versions are affected by RUSTSEC-2026-0397?
1 open source package ship an affected version, including zstd-safe.
| Package | Affected | Fixed in |
|---|---|---|
zstd-safe crates.io | From 4.0.0 | 8.2.0 |
How do I fix RUSTSEC-2026-0397?
Upgrade zstd-safe to 8.2.0 or later.
Is RUSTSEC-2026-0397 being exploited?
There is no known exploitation of RUSTSEC-2026-0397 in the wild and no public exploit code.