Cross-site Scripting (XSS) Affecting nextcloud-server-33 package, versions <33.0.7-r5


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.31% (21st percentile)

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  • Snyk IDSNYK-CHAINGUARDLATEST-NEXTCLOUDSERVER33-20415986
  • published4 Oct 2026
  • disclosed24 Jul 2026

Introduced: 24 Jul 2026

CVE-2026-66010  (opens in a new tab)
CWE-79  (opens in a new tab)

How to fix?

Upgrade Chainguard nextcloud-server-33 to version 33.0.7-r5 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream nextcloud-server-33 package and not the nextcloud-server-33 package as distributed by Chainguard. See How to fix? for Chainguard relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1