# Apache FreeMarker template loading mechanism vulnerable to path traversal

Advisory record · `GHSA-27j2-h3m2-8237`

- **Identifiers:** `GHSA-27j2-h3m2-8237` · `CVE-2026-84939`
- **State:** Confirmed
- **Severity:** CVSS 9.1 Critical
- **Critical:** Yes: CVSS 9+
- **Weakness (CWE):** [CWE-23](https://cwe.mitre.org/data/definitions/23.html)
- **Tags:** [Path traversal](https://agentprime.io/advisories/tag/path-traversal.md)
- **Published:** 10 Sept 2026
- **Updated:** 24 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 10 Sept 2026, 06:31 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Critical

Critical, because:

- CVSS score 9.1: 9.0 or more.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected packages

- `org.freemarker:freemarker` (Maven): affected `>=2.2.0, <2.3.35`; fixed in `2.3.35`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Apache FreeMarker from 2.2.0 through 2.3.34 is vulnerable to path traversal in its template loading mechanism. An attacker who can supply a malformed locale identifier to FreeMarker can exploit this when localized lookup is enabled, which is the default. Upgrade to version 2.3.35; disabling localized lookup also mitigates the issue in earlier versions. Files remain limited by the configured TemplateLoader, so FileTemplateLoader still blocks access outside its base directory.

Written 2 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 9.1 Critical, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`, from GitHub Advisory Database

- **CISA KEV:** Not listed.
- **EPSS:** 0.0085, the 58th percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:16 UTC: First seen by agentprime
- 31 Oct 2026, 14:16 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-27j2-h3m2-8237)

## Sources

- [GitHub Advisory Database: GHSA-27j2-h3m2-8237](https://github.com/advisories/GHSA-27j2-h3m2-8237)
- [OSV: GHSA-27j2-h3m2-8237](https://osv.dev/vulnerability/GHSA-27j2-h3m2-8237)
- <https://nvd.nist.gov/vuln/detail/CVE-2026-84939>
- <https://github.com/apache/freemarker/commit/83953d9a9fa5a7c1fce3e39ff57182c19a34b5eb>
- <https://github.com/apache/freemarker>
- <https://github.com/apache/freemarker/releases/tag/v2.3.35>
- <https://lists.apache.org/thread/hrd7o2ylwkkswdyhyzllgqt0f80kyd5y>
- <http://www.openwall.com/lists/oss-security/2026/09/08/2>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-27j2-h3m2-8237>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-27j2-h3m2-8237/>. Everything for agents: <https://agentprime.io/llms.txt>.