High-severity RCE-capable path traversal in a widely used Java templating engine (FreeMarker). Many web apps use it; exploit can enable remote compromise—worthy of broad IT/security notice.
CVE-2026-84939
Locale-based path traversal in Apache FreeMarker enabling arbitrary template access and possible RCE
Is CVE-2026-84939 being exploited?
Not confirmed. CVE-2026-84939 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 0.83% probability of exploitation in the next 30 days.
How severe is CVE-2026-84939?
CVE-2026-84939 is rated Critical with a CVSS score of 9.1. 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-2026-84939?
Yes. A fix has been recorded for CVE-2026-84939. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-84939 affect?
CVE-2026-84939 affects Apache FreeMarker 2.2.0 - 2.3.34, Java web applications using FreeMarker, Apps using permissive TemplateLoader implementations. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-84939?
Upgrade to FreeMarker 2.3.35 or disable localized lookup until patched
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Malformed locale lookup enables path traversal to read/load arbitrary templates; can lead to remote code execution depending on TemplateLoader and app context.
Immediate action required
- affected>= 2.2.0 and <= 2.3.34
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.