Bug 2570275 (CVE-2026-125108)

Summary:	CVE-2026-125108 rack: rack: Security inspection bypass via multipart boundary parsing differential
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	akostadi, amasferr, crizzo, dmayorov, eglynn, eshamard, jjoyce, jlledo, jpretori, jschluet, jvasik, kaycoth, lhh, mburns, mgarciac, pantinor, rblanco, rhel-process-autobot, tsedmik, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in Rack. When parsing multipart requests, Rack can skip an invalid or empty leading boundary parameter in the Content-Type header and process a subsequent boundary instead. A remote attacker can exploit this issue by sending specially crafted multipart requests that intermediate security proxies or Web Application Firewalls (WAFs) interpret differently than Rack. This parsing inconsistency can allow malicious form fields or file uploads to bypass upstream security inspections and reach the backend application directly.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
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Description OSIDB Bzimport 2026-11-10 19:47:37 UTC

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.