Vulnerability · Published Jul 27, 2026 · Assigned by VulnCheck
CVE-2026-66730facil.io 0.6.0 - 0.7.6 Infinite Loop DoS via Multipart MIME Body Parser
High 7.5
In plain English
A high-severity infinite loop in facil.io from boazsegev. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 56% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.
Official description
facil.io 0.6.0 through 0.7.6 contains a denial-of-service vulnerability in the multipart body parser that allows an unauthenticated remote attacker to permanently freeze worker processes at 100% CPU by sending a multipart/form-data request with a partial closing boundary. The missing progress guard in the parser loop causes http_mime_parse to return 0 bytes consumed without setting done or error flags, causing the calling loop to re-invoke the parser on the same buffer indefinitely, exhausting all workers and permanently disabling the server until manually restarted.
Affected products (as reported)
Weakness: CWE-835 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- Researcher Blog technical-description, exploit
- Researcher Disclosure technical-description, exploit
- https://www.vulncheck.com/advisories/facil-io-infinite-loop-dos-via-multipart-mime-body-parser third-party-advisory