CVE-2026-66917
Stored XSS in JoomGallery <4.4.0 allows persistent JS execution in visitors' browsers
Is CVE-2026-66917 being exploited?
Not confirmed. CVE-2026-66917 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.47% probability of exploitation in the next 30 days.
How severe is CVE-2026-66917?
CVE-2026-66917 is rated High with a CVSS score of 8.6. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-66917?
Yes. A fix has been recorded for CVE-2026-66917. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-66917 affect?
CVE-2026-66917 affects JoomGallery <4.4.0, joomgalleryfriends.net extension, Joomla CMS sites running the extension. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-66917?
Upgrade JoomGallery to >=4.4.0; sanitize/remove uploaded content; restrict uploader privileges
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated privileged user can store JavaScript in images, causing persistent XSS to steal sessions, enable account takeover, or deliver malware to visitors.
Patch when possible
- affected4.0.0-4.3.0
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.