CVE-2026-66730 facil.io 0.6.0 - 0.7.6 Infinite Loop DoS via Multipart MIME Body Parser
An unauthenticated remote attacker can cause a permanent denial of service by sending a malformed multipart request that triggers an infinite loop in the parser.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-66730?
CVE-2026-66730 is a high-severity denial of service vulnerability in boazsegev facil.io, published on 27 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-835
Which versions are affected by CVE-2026-66730?
How do I fix CVE-2026-66730?
No fix has been published for CVE-2026-66730 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-66730 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-66730 exists.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as GHSA-gc74-g85r-w7x5.