PatchTheCVECVE-2021-29939: An issue was discovered in the stackvector crate through 2021-02-19 for Rust
CVE-2021-29939 is a high-severity flaw (CVSS 7.3) affecting stackvector. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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.
Why this priority
- High severity
- Public exploit reference
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.3 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 1.0% (top 36%) |
| CISA exploited list | No |
| Weakness | CWE-787 |
| Published | 2021-04-01 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2021-29939?
stackvector: upgrade to 1.0.9. Exact commands for each OS are on this page.
Is CVE-2021-29939 being exploited?
CVE-2021-29939 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2021-29939 affect?
CVE-2021-29939 affects stackvector. Severity is high (CVSS 7.3). 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.
How urgent is CVE-2021-29939?
Priority 51/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action