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 pro
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.
Details
Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-66730
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-667300.47% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 38% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-66730 | coverage & exploitation status | NVD · CVE.org |
Recent advisories for facil.io
A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.
- highCVE-2026-66731: facil.io 0.7.5 through 0.7.6 contains a denial-of-service vulnerability in the HTTP/1.1 chunke…nvd · 2026-07-27
- highCVE-2026-66729: facil.io 0.6.0 through 0.7.6 contains an integer underflow vulnerability in the multipart MIME…nvd · 2026-07-27
- mediumCVE-2026-16653: A security flaw has been discovered in boazsegev facil.io up to 0.7.58. This affects the funct…nvd · 2026-07-23
- highCVE-2026-16632: A flaw has been found in boazsegev facil.io up to 0.7.4. Affected is the function websocket_on…nvd · 2026-07-23
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