Bug 2429959 (CVE-2026-0990)

Summary:	CVE-2026-0990 libxml2: libxml2: Denial of Service via uncontrolled recursion in XML catalog processing
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	adudiak, caswilli, crizzo, csutherl, gtanzill, jbuscemi, jclere, jmitchel, kaycoth, kshier, pbohmill, pjindal, plodge, stcannon, szappis, teagle, vchlup, yguenane
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in libxml2, an XML parsing library. This uncontrolled recursion vulnerability occurs in the xmlCatalogXMLResolveURI function when an XML catalog contains a delegate URI entry that references itself. A remote attacker could exploit this configuration-dependent issue by providing a specially crafted XML catalog, leading to infinite recursion and call stack exhaustion. This ultimately results in a segmentation fault, causing a Denial of Service (DoS) by crashing affected applications.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2429960, 2429961, 2429962, 2429963, 2429964, 2429965, 2429966, 2429967, 2429968, 2429969, 2429970, 2429971
Bug Blocks:

Description OSIDB Bzimport 2026-01-15 13:19:31 UTC

Uncontrolled recursion vulnerability in the xmlCatalogXMLResolveURI function of the libxml2 XML parsing library. The issue occurs when an XML catalog contains a delegate URI entry that references the catalog itself. During entity resolution, the function recursively resolves the same catalog entry without detecting the cyclic reference. This results in infinite recursion and eventual call stack exhaustion, leading to a segmentation fault. Exploitation is configuration-dependent and primarily impacts availability by allowing an attacker to crash affected applications.