CVE-2026-125108lowCWE-436

CVE-2026-125108: low-severity vulnerability in rack

Rack: Multipart boundary ambiguity guard in Rack::Multipart::Parser can be bypassed with a quoted boundary value, allowing WAF bypass

Published

Follow this CVE+ Monitor rack

E-mail alert when it lands in KEV, gets a public PoC or its score goes up.

5Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 3.7
Rack is a modular Ruby web server interface. Prior to 2.2.25, 3.1.23, and 3.2.8, Rack::Multipart::Parser.parse_boundary can skip a leading empty or quoted boundary parameter in a multipart Content-Type header and accept a later parameter. Rack can therefore parse a request body with a boundary that a conforming intermediary would not derive, allowing form fields or file uploads to reach an application without the intended proxy or web application firewall inspection. This issue is fixed in versions 2.2.25, 3.1.23, and 3.2.8.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Affected products
rack · rack
Related CVEs — rack

In the same product, most dangerous first.

CVE-2024-25126MEDIUMRack ReDos in content type parsing (2nd degree polynomial)EPSS 35.4%CVE-2019-16782MEDIUMPossible Information Leak / Session Hijack Vulnerability in RackEPSS 3.7%CVE-2024-26146MEDIUMPossible Denial of Service Vulnerability in Rack Header ParsingEPSS 2.0%CVE-2024-26141MEDIUMPossible DoS Vulnerability with Range Header in RackEPSS 1.6%CVE-2025-46727HIGHUnbounded-Parameter DoS in Rack::QueryParserEPSS 1.2%CVE-2025-25184MEDIUMPossible Log Injection in Rack::CommonLoggerEPSS 1.2%