Bug 2506426 (CVE-2026-65904)

Summary: CVE-2026-65904 DOMPurify: DOMPurify: Cross-Site Scripting via unsanitized DOM elements from different realms
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: 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, ttakamiy, vereddy, vlaad, watson-tool-maintainers, wtam, xdharmai, yfang, yguenane
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in DOMPurify. When DOM elements originating from a different window or realm, such as an iframe's contentDocument, are processed in IN_PLACE mode, DOMPurify fails to properly sanitize them. This oversight allows an attacker to inject and execute Cross-Site Scripting (XSS) payloads, potentially leading to information disclosure or other malicious actions within the user's browser session. Exploitation requires user interaction and has high attack complexity.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2522237, 2522242, 2522243, 2522244, 2522250, 2522251, 2522247, 2522248    
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Description OSIDB Bzimport 2026-07-23 14:01:25 UTC 
DOMPurify through 3.3.3 fails to sanitize DOM elements passed via IN_PLACE mode when the element originates from a different window/realm (e.g., an iframe's contentDocument). A cross-realm instanceof check in the private _isNode() function returns false for foreign-realm nodes, causing DOMPurify to stringify the element (yielding '[object HTMLDivElement]'), silently reset IN_PLACE to false, and return the unsanitized element unchanged with any XSS payloads intact. The vendor considers this an edge case outside DOMPurify's threat model and, at time of publication, no fix was planned.