CVE-2026-84673
Stored XSS in Jenkins Customizable Header Plugin via malicious SVG icon.
Is CVE-2026-84673 being exploited?
Not confirmed. CVE-2026-84673 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 0.29% probability of exploitation in the next 30 days.
How severe is CVE-2026-84673?
CVE-2026-84673 is rated High with a CVSS score of 8.8. 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-2026-84673?
Yes. A fix has been recorded for CVE-2026-84673. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-84673 affect?
CVE-2026-84673 affects Jenkins Customizable Header Plugin <=295.v2544b_ca_19b_97, Jenkins servers with the plugin installed. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-84673?
Update plugin to the fixed version; remove/untrust custom SVG icons and restrict Jenkins UI access.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Stored XSS allows attackers to execute JS in Jenkins UI, steal sessions, perform actions as users, or manipulate admin interfaces.
Immediate action required
- affected<= 295.v2544b_ca_19b_97
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.