Affects widely used enterprise collaboration platform (Atlassian Confluence). Enables account takeover and system compromise across many orgs; newsworthy and broadly impactful.
CVE-2026-21580
Stored XSS and privilege escalation in Atlassian Confluence Server/Data Center
Is CVE-2026-21580 being exploited?
Not confirmed. CVE-2026-21580 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 0.40% probability of exploitation in the next 30 days.
How severe is CVE-2026-21580?
CVE-2026-21580 is rated Critical with a CVSS score of 9.3. 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-2026-21580?
Yes. A fix has been recorded for CVE-2026-21580. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-21580 affect?
CVE-2026-21580 affects Atlassian Confluence Data Center, Atlassian Confluence Server, Affected releases include multiple 7.x–10.2.0 builds (see vendor for specific versions). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-21580?
Upgrade to Confluence >=9.2.21 or >=10.2.13 immediately
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated stored XSS allows arbitrary JS in victims' browsers, enabling higher-privilege actions, account takeover and potential system access.
Immediate action required
- affected10.2.0 to 10.2.11
- affected10.1.0 to 10.1.2
- affected10.0.2 to 10.0.3
- affected9.5.1 to 9.5.4
- affected9.4.0 to 9.4.1
- affected9.3.1 to 9.3.2
- affected9.2.0 to 9.2.20
- affected9.1.0 to 9.1.1
- affected9.0.3
- affected8.9.6 to 8.9.8
- affected8.5.15 to 8.5.31
- affected7.19.27 to 7.19.30
- affected8.5.15 to 8.5.31
- affected7.19.27 to 7.19.30
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.