CVE-2022-31142 is a high-severity (CVSS 7.5) CWE-208 vulnerability in fastify-bearer-auth. A fix is available for fastify-bearer-auth — see the affected versions and patch details below.
Potential Timing Attack Vector in @fastify/bearer-auth
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2022-31142.
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
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
fastify-bearer-authnpm@fastify/bearer-authnpmDescription
Impact
fastify-bearer-auth does not securely use crypto.timingSafeEqual. A malicious attacker could estimate the length of one valid bearer token. According to the corresponding RFC 6750, the bearer token has only base64 valid characters, reducing the range of characters for a brute force attack.
All versions of fastify-bearer-auth are also affected.
Patches
We released:
- v8.0.1 with a fix for the Fastify v4 line
- v7.0.2 with a fix for the Fastify v3 line
Workarounds
There are no workarounds. Update your dependencies.
References
https://hackerone.com/reports/1633287
For more information
If you have any questions or comments about this advisory:
- Open an issue in https://github.com/fastify/fastify-bearer-auth
- Email us at [email protected]
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | fastify-bearer-auth | ≥ 5.0.1 | No fix |
| 📦npm | @fastify/bearer-auth | all versions | 7.0.2npm install @fastify/bearer-auth@7.0.2 |
| 📦npm | @fastify/bearer-auth | ≥ 8.0.0&&< 8.0.1 | 8.0.1npm install @fastify/bearer-auth@8.0.1 |
Affected Products
bearer-authfastifyDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for fastify-bearer-auth, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
A fix is available for CVE-2022-31142; check the affected-versions list above or the advisory for the patched release of fastify-bearer-auth, then make sure no transitive dependency still pins the vulnerable range.
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-2022-31142 in your dependencies?
Find it across npm, including transitive dependencies.