CVE-2026-66729 — facil.io 0.6.0 - 0.7.6 Integer Underflow DoS via Multipart MIME Body Parser
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 proce…
Published: 2026-07-27 · CVSS: 8.7 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7