Bug 2506431 (CVE-2026-65902)

Summary:	CVE-2026-65902 dompurify: DOMPurify: Sanitization bypass via hook manipulation
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	abarbaro, akhatavk, akostadi, alizardo, amasferr, amctagga, anjoseph, anpicker, aoconnor, aos-team-art-private, asdas, ataylor, bniver, bparees, cdrage, dbruscin, dkeler, dmayorov, dpaolell, dschmidt, ehugonne, ewittman, flucifre, fmariani, gmalinko, gmeno, gparvin, groman, hasun, janstey, jchui, jdelft, jfula, jhe, jlanda, jlledo, jowilson, jprabhak, jupierce, jwong, jwon, kaycoth, kbempah, kshier, ktsao, kvanderr, lchilton, lgarciaa, mbenjamin, mbiarnes, mcarlett, mhackett, nboldt, nipatil, nyancey, oaljalju, omaciel, ometelka, pantinor, pjindal, ppalepu, ppostler, prdhamdh, psrna, ptisnovs, rhaigner, rhel-process-autobot, rkubis, rstepani, rushinde, sdawley, sfeifer, sghai, sidsharm, simaishi, solenoci, sostapov, stcannon, suppawar, syedriko, tcunning, teagle, thason, tsedmik, vereddy, vlaad, watson-tool-maintainers, wtam, xdharmai, yfang, yguenane
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in DOMPurify. An attacker can exploit a vulnerability in how DOMPurify handles its sanitization hooks when default configurations are used. By manipulating the uponSanitizeElement or uponSanitizeAttribute hooks, an attacker can permanently alter the allowed HTML tags and attributes. This allows malicious content to bypass sanitization, potentially leading to cross-site scripting (XSS) attacks and compromising the integrity of web 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:	2520400, 2520404, 2520410, 2520430, 2520436, 2520440, 2520485, 2520487, 2520489, 2520507, 2520402, 2520408, 2520412, 2520414, 2520418, 2520422, 2520427, 2520432, 2520486, 2520488, 2520490, 2520491, 2520492, 2520493, 2520504, 2520518
Bug Blocks:

Description OSIDB Bzimport 2026-07-23 14:01:42 UTC

DOMPurify before 3.4.7 (affected versions <= 3.4.5) passes direct references to the module-level DEFAULT_ALLOWED_TAGS and DEFAULT_ALLOWED_ATTR sets to the uponSanitizeElement and uponSanitizeAttribute hooks via data.allowedTags / data.allowedAttributes when sanitize is called without an explicit cfg.ALLOWED_TAGS / cfg.ALLOWED_ATTR array. A hook that mutates these fields permanently widens the default allow-lists for the lifetime of the DOMPurify instance, so all subsequent default-config sanitize calls inherit the widened defaults and attacker payloads using the poisoned tag/attribute name survive sanitization. removeAllHooks(), clearConfig(), and passing a fresh cfg do not recover the state; only constructing a new DOMPurify instance does.