Bug 2506731 (CVE-2026-66010)

Summary: CVE-2026-66010 dompurify: DOMPurify: Cross-Site Scripting (XSS) via custom element attribute bypass
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: aazores, abarbaro, abrianik, akhatavk, akostadi, alizardo, amasferr, amctagga, anjoseph, anpicker, aoconnor, aos-team-art-private, asdas, ataylor, bniver, cdrage, chfoley, cmah, dbruscin, dkeler, dmayorov, dpaolell, dschmidt, eaguilar, ebaron, ehugonne, ewittman, flucifre, fmariani, ggrzybek, gmalinko, gmeno, gparvin, groman, hasun, janstey, jchui, jdelft, jfula, jhe, jlanda, jlledo, jmatsuok, jowilson, jprabhak, jraez, jtolenti, jupierce, jwong, jwon, kaycoth, kbempah, kshier, ktsao, kvanderr, lchilton, lgarciaa, mbenjamin, mbiarnes, mcarlett, mhackett, nboldt, nipatil, nyancey, oaljalju, omaciel, ometelka, pantinor, parichar, pjindal, ppalepu, ppostler, prdhamdh, psrna, ptisnovs, rgodfrey, rhaigner, rhel-process-autobot, rkubis, rstepani, rushinde, sdawley, sfeifer, sghai, sidsharm, simaishi, solenoci, sostapov, stcannon, suppawar, swoodman, syedriko, tasato, tcunning, teagle, thason, tsedmik, ttakamiy, vereddy, vlaad, watson-tool-maintainers, wtam, xdharmai, yfang, yguenane
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in DOMPurify. This vulnerability allows attackers to bypass application security policies by preserving sensitive attributes on custom elements. These attributes can then be re-injected into web page content, leading to Cross-Site Scripting (XSS) attacks. An attacker could exploit this to execute malicious scripts in a user's browser, potentially leading to information disclosure or unauthorized actions.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2506835, 2506836, 2506838, 2506839, 2506840, 2506842, 2506846, 2506848, 2506837, 2506841, 2506843, 2506844, 2506845, 2506847, 2506849, 2506850, 2509213, 2509214    
Bug Blocks:    

Description OSIDB Bzimport 2026-07-24 13:02:21 UTC
DOMPurify before 3.4.12 fails to execute afterSanitizeElements hook for custom elements allowed via CUSTOM_ELEMENT_HANDLING.tagNameCheck, allowing attributes to bypass application security policies. Attackers can preserve sensitive attributes on custom elements that later re-inject them into innerHTML sinks, creating second-order XSS gadgets.