What’s Vulnerable › Vulnerabilities

CVE-2026-66730: facil.io 0.6.0 - 0.7.6 Infinite Loop DoS via Multipart MIME Body Parser

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-27 · updated 2026-10-24
• Weakness: CWE-835

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

• boazsegev facil.io: from 0.6.0 through 0.7.6

References

• https://github.com/theopaid/Infinite-Loop-DoS-in-facil.io-MIME-Parser
• https://tpaidakis.com/writeups/facilio-parser-dos/
• https://www.vulncheck.com/advisories/facil-io-infinite-loop-dos-via-multipart-mime-body-parser

Get alerted when CVE-2026-66730 or the next vulnerability affects your stack