CVE-2021-31919 is a high-severity (CVSS 7.5) CWE-909 vulnerability in rkyv. A fix is available for rkyv — see the affected versions and patch details below.
Use of uninitialized buffer in rkyv
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
rkyvReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
An issue was discovered in the rkyv crate before 0.6.0 for Rust. When an archive is created via serialization, the archive content may contain uninitialized values of certain parts of a struct.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | rkyv | all versions | 0.6.0cargo update -p rkyv --precise 0.6.0 |
Affected Products
rkyvrkyv_projectDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rkyv, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update rkyv to 0.6.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-31919 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2021-31919 in your dependencies?
Find it across crates.io, including transitive dependencies.