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CVE-2026-66729 Details

ANALYZED

This CVE record has been analyzed and enriched by NVDAPI.com as an independent party.

Description

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.

Metrics

CVSS 3.x Severity and Vector Strings:

VolerionCVSS-B:6.5 MEDIUMVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

CNA: [email protected]CVSS-B:7.5 HIGHVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://github.com/theopaid/Out-of-Bounds-Read-in-facil.io-MIME-Parser-leads-to-Server-Crash	[email protected]	Technical Analysis
https://tpaidakis.com/writeups/facilio-parser-dos/	[email protected]
https://www.vulncheck.com/advisories/facil-io-integer-underflow-dos-via-multipart-mime-body-parser	[email protected]	Advisory

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-125	Out-of-bounds Read	[email protected]

Affected Products

Product	Versions
facil.io	>= 0.6.0, <= 0.7.6 (semver)
CPE No CPEs found in CPE dictionary for this product. Remediation No remediation found in references.

Change History

4 change records found show changes

Date	Action	Recorded By
Jul 31, 2026	CVE Modified	[email protected]
Jul 27, 2026	CVE Modified	[email protected]
Jul 27, 2026	CVE Modified	CISA-ADP
Jul 27, 2026	New CVE Received	[email protected]