Vulnerability Description
facil.io 0.6.0 through 0.7.6 contains an integer underflow vulnerability in the multipart MIME body parser that allows unauthenticated remote attackers to crash the server process by sending a crafted Content-Disposition header with an empty field name. Attackers can trigger a uint32_t wraparound in http_mime_parser.h causing an out-of-bounds memory read past the name pointer, resulting in a bus fault that crashes the handling worker with a single POST request.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/theopaid/Out-of-Bounds-Read-in-facil.io-MIME-Parser-leads-to-
- https://tpaidakis.com/writeups/facilio-parser-dos/
- https://www.vulncheck.com/advisories/facil-io-integer-underflow-dos-via-multipar
FAQ
What is CVE-2026-66729?
CVE-2026-66729 is a vulnerability with a CVSS score of 7.5 (HIGH). facil.io 0.6.0 through 0.7.6 contains an integer underflow vulnerability in the multipart MIME body parser that allows unauthenticated remote attackers to crash the server process by sending a crafted...
How severe is CVE-2026-66729?
CVE-2026-66729 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-66729?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.