CVE-2021-45686 is a critical-severity (CVSS 9.8) CWE-908 vulnerability in csv-sniffer. A fix is available for csv-sniffer — see the affected versions and patch details below.
Use of Uninitialized Resource in csv-sniffer.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-45686 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
csv-snifferReal-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
Affected versions of this crate passes an uninitialized buffer to a user-provided Read implementation (within fn preamble_skipcount()).
Arbitrary Read implementations can read from the uninitialized buffer (memory exposure) and also can return incorrect number of bytes written to the buffer. Reading from uninitialized memory produces undefined values that can quickly invoke undefined behavior.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | csv-sniffer | all versions | 0.2.0cargo update -p csv-sniffer --precise 0.2.0 |
Affected Products
csv-sniffercsv-sniffer_projectDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for csv-sniffer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update csv-sniffer to 0.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-45686 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-2021-45686 in your dependencies?
Find it across crates.io, including transitive dependencies.