Bug 2564254 (CVE-2026-61847)

Summary:	CVE-2026-61847 crass: crass: Denial of Service via excessive recursion when processing comments
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	akostadi, amasferr, dmayorov, ehelms, eshamard, jlledo, jpasqual, juwatts, jvasik, kaycoth, lblicha, mhulan, ogajduse, osousa, pantinor, rblanco, rchan, smallamp, tsedmik, zhunting
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in crass. A remote attacker can cause a Denial of Service (DoS) by submitting a specially crafted stylesheet containing a large number of adjacent comments. Because the parser recursively processes comments when discarding them, handling these consecutive comments triggers excessive recursion that crashes the application.	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 2026-10-30 19:19:17 UTC

Crass is a Ruby CSS parser that's fully compliant with the CSS Syntax Level 3 specification. Prior to 1.0.7, when the `:preserve_comments` option is not enabled, which is the default, Crass discards CSS comments by recursively consuming the next token. An attacker-provided stylesheet containing a very large number of adjacent comments can cause excessive recursion and trigger a `SystemStackError`, denying service to the parsing application. Preserving comments avoids this recursive path. This issue is fixed in version 1.0.7.