CVE-2026-66729

facil.io 0.6.0 - 0.7.6 Integer Underflow DoS via Multipart MIME Body Parser

HIGH
7.5
CVSS Score
Published: July 27, 2026 at 04:52 PM UTC
Updated: October 24, 2026 at 01:10 PM UTC
1 product affected across 1 vendorFacil.io

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Severity
HIGH7.5
Exploit prediction
EPSS 0.8%
SSVC
PoC

Description

facil.io 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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0.6.0 ≤ v ≤ 0.7.60.6.0

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-125

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