CVE-2022-39288 is a high-severity (CVSS 7.5) CWE-754 vulnerability in fastify. EPSS puts its 30-day exploitation probability at 59.2% (99th percentile). A fix is available for fastify — see the affected versions and patch details below.
Denial of service in Fastify via Content-Type header
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-2022-39288.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2022-39288 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE sits: patch-first territory.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
fastifynpmDescription
fastify is a fast and low overhead web framework, for Node.js. Affected versions of fastify are subject to a denial of service via malicious use of the Content-Type header. An attacker can send an invalid Content-Type header that can cause the application to crash. This issue has been addressed in commit fbb07e8d and will be included in release version 4.8.1. Users are advised to upgrade. Users unable to upgrade may manually filter out http content with malicious Content-Type headers.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | fastify | ≥ 4.0.0&&< 4.8.1 | 4.8.1npm install fastify@4.8.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for fastify, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update fastify to 4.8.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-39288 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2022-39288 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2022-39288. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2022-39288 in your dependencies?
O3 Security finds CVE-2022-39288 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.