Apache FreeMarker template loading mechanism vulnerable to path traversal

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

9.1 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS

• CVE-2026-84939: 0.85% estimated exploitation activity in the next 30 days; percentile 58.36 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Path traversal vulnerability in Apache FreeMarker template loading mechanism, if the attacker can specify an arbitrary malformed locale identifier to FreeMarker, and the localized lookup configuration setting is enabled (it's by default enabled). This issue affects Apache FreeMarker from 2.2.0 through 2.3.34. Users are recommended to upgrade to version 2.3.35. Disabling localized lookup in previous versions also mitigates this. Note that even in versions affected by this vulnerability, the files that can be loaded remain restricted by the TemplateLoader that FreeMarker is configured to use. In particular, FileTemplateLoader prevents attempts to traverse outside the baseDir specified in its constructor. Other TemplateLoader implementations may allow access outside their designated base directory, but they are still constrained by the underlying storage mechanism—for example, a loader wrapping a Java class loader can only access resources that the class loader can load, while one…

Published by the source

10 Sep 2026, 06:31 UTC

Last modified by the source

24 Sep 2026, 19:15 UTC

Source last checked

26 Oct 2026, 16:55 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-27j2-h3m2-8237

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-27j2-h3m2-8237

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# Patch Next advisory brief: CVE-2026-84939

Advisory: Apache FreeMarker template loading mechanism vulnerable to path traversal
IDs: CVE-2026-84939, GHSA-27j2-h3m2-8237
Record: https://patchnext.com/advisories/cve-2026-84939 (revision 2, source checked 26 Oct 2026, 16:55 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.freemarker:freemarker 2.3.35. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.freemarker:freemarker: affected >= 2.2.0, <= 2.3.34; fixed in 2.3.35

## Suggested inspection (read-only)
- Maven org.freemarker:freemarker: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.freemarker:freemarker.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-27j2-h3m2-8237 (OSV record GHSA-27j2-h3m2-8237 lists affected ranges: Maven org.freemarker:freemarker >=2.2.0 <2.3.35 (fixed))
- Verified: https://github.com/advisories/GHSA-27j2-h3m2-8237 (GitHub-reviewed advisory GHSA-27j2-h3m2-8237 lists affected ranges: Maven org.freemarker:freemarker >=2.2.0 <=2.3.34)

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