CVE-2026-66730

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.

CVSS 4.0

8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.8% chance of exploitation in the next 30 days; higher than 55% of CVEs (scores of 2026-10-25)

CWE

CWE-835

Published

2026-07-27

Modified

2026-10-24

Record from

the NVD, synced 2026-10-24

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

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