CVE-2026-66731— facil.io 0.7.5 - 0.7.6 HTTP/1.1 Chunked Transfer Encoding Parser Crash DoS
Possible ATT&CK Techniques 1AI
T1499 · Endpoint Denial of ServiceGet alerts for future matching vulnerabilitiesLog in to subscribe
I. Basic Information for CVE-2026-66731
Vulnerability Information
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Vulnerability Title
facil.io 0.7.5 - 0.7.6 HTTP/1.1 Chunked Transfer Encoding Parser Crash DoS
Source: CVE Program / CVE List V5
Vulnerability Description
facil.io 0.7.5 through 0.7.6 contains a denial-of-service vulnerability in the HTTP/1.1 chunked transfer encoding parser that allows unauthenticated remote attackers to crash the server by sending a negative chunk size value. Attackers can send a single POST request with a Transfer-Encoding: chunked header containing a leading minus sign in the chunk size field, causing the parser in http1_parser.h to compute a large positive integer from the negated value, corrupting internal state and moving the read pointer into unmapped memory resulting in a fault.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
跨界内存读
Source: CVE Program / CVE List V5
Affected Products
II. Public POCs for CVE-2026-66731
| # | POC Description | Source Link | Shenlong Link |
|---|
AI-Generated POCPremium
Qwen3.6-35B-A3B · 6591 chars
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III. Intelligence Information for CVE-2026-66731
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Vendor Advisories for CVE-2026-66731 (1)
Proof of Concept for CVE-2026-66731 (1)
Security Blog Posts for CVE-2026-66731 (1)
- 🔗 When Zero Minus One Is Four Billion: Three Unauthenticated DoS Bugs in facil.io — tpaidakis Read full article technical-descriptionexploit
Same Patch Batch · boazsegev · 2026-07-27 · 3 CVEs total
| CVE-2026-66729 | 7.5 HIGH | facil.io 0.6.0 - 0.7.6 Integer Underflow DoS via Multipart MIME Body Parser |
| CVE-2026-66730 | 7.5 HIGH | facil.io 0.6.0 - 0.7.6 Infinite Loop DoS via Multipart MIME Body Parser |
IV. Related Vulnerabilities
Same product: facil.io
- CVE-2026-66730
facil.io 0.6.0 - 0.7.6 Infinite Loop DoS via Multipart MIME - CVE-2026-66729
facil.io 0.6.0 - 0.7.6 Integer Underflow DoS via Multipart M - CVE-2026-16653
boazsegev facil.io Public Folder http.c http_sendfile2 path - CVE-2026-16632
boazsegev facil.io WebSocket Frame websocket_parser.h websoc - CVE-2026-41146
facil.io and downstream iodine ruby gem vulnerable to uncont
Same vendor: boazsegev
- CVE-2026-66730
facil.io 0.6.0 - 0.7.6 Infinite Loop DoS via Multipart MIME - CVE-2026-66729
facil.io 0.6.0 - 0.7.6 Integer Underflow DoS via Multipart M - CVE-2026-16653
boazsegev facil.io Public Folder http.c http_sendfile2 path - CVE-2026-16632
boazsegev facil.io WebSocket Frame websocket_parser.h websoc - CVE-2026-41146
facil.io and downstream iodine ruby gem vulnerable to uncont
Same weakness: CWE-125
- CVE-2026-50126
adaguc-server GeoJSON coordinate parser (CConvertGeoJSON.cpp - CVE-2026-75904
libmodplug <= 0.8.9.1 - Out-of-Bounds Read in pat_smplooped - CVE-2026-63632
ONNX: Heap-Buffer-Overflow READ in Gemm Version Converter Ad - CVE-2026-75032
Bluez: bluez: out-of-bounds read in avrcp parse_media_elemen - CVE-2026-23935
Use-after-free read in script item/preprocessing HttpRequest
V. Comments for CVE-2026-66731
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