Bug 2520467

Summary: CVE-2026-65913 nextcloud: DOMPurify: Cross-Site Scripting (XSS) via prototype pollution in USE_PROFILES mode [fedora-all]
Product: [Fedora] Fedora Reporter: Ganesh <gnaik>
Component: nextcloudAssignee: Andrew Bauer <zonexpertconsulting>
Status: CLOSED CURRENTRELEASE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
Version: rawhideCC: pampelmuse, zonexpertconsulting
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["8c4b2e97-0528-49d9-a541-f40335b4bbb0"]}
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Doc Text:
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Last Closed: 2026-08-20 16:35:14 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On:    
Bug Blocks: 2506429    

Description Ganesh 2026-08-20 16:03:59 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

DOMPurify before 3.3.2 contains a prototype pollution vulnerability in USE_PROFILES mode that allows attackers to bypass attribute filtering by polluting Array.prototype properties. Attackers can set Array.prototype properties like onclick to true, causing DOMPurify to accept event handlers as allowlisted attributes and resulting in DOM-based XSS when sanitized markup is rendered.
Comment 1 Andrew Bauer 2026-08-20 16:35:14 UTC 
This bug is not valid. As of this writing, the current Nextcloud 34.0.3 release contain DOMPurify 3.4.13 which does not contain this CVE.

See:
https://github.com/nextcloud/server/blob/v34.0.3/package-lock.json#L6512