Service crash via prototype-named Content-Type values
Published Oct 10, 2022 · Updated Apr 23, 2025
Improper exceptional-condition handling in Fastify 4.0.0 through 4.8.0 allows remote attackers to crash the service via Content-Type headers. The ContentTypeParser stores parsers in a plain object and applies prototype-sensitive membership lookups to attacker-controlled header values, so inherited names such as constructor resolve to non-parser properties. No authentication or user interaction is required, and a crafted request can terminate the Node.js application process without reading or changing data.
Summary
What happened
Improper exceptional-condition handling in Fastify 4.0.0 through 4.8.0 allows remote attackers to crash the service via Content-Type headers. The ContentTypeParser stores parsers in a plain object and applies prototype-sensitive membership lookups to attacker-controlled header values, so inherited names such as constructor resolve to non-parser properties. No authentication or user interaction is required, and a crafted request can terminate the Node.js application process without reading or changing data.
The record
- CVE
- CVE-2022-39288
- Published
- Oct 10, 2022
- Updated
- Apr 23, 2025
- Vendor
- Fastify
- Product
- Fastify
- Classifications
- CWE-754, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 10, 2022CVE publishedPublication date reported by the CVE source.
- Apr 23, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 4.0.0, < 4.8.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Fastify malicious Content-Type regression casesproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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