# CVE-2026-103088: Path traversal in handlebars.java

> Attackers can read arbitrary files outside the template directory in Spring MVC apps using Handlebars.java with file-based templates.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 30 Sep 2026
- **Updated:** 30 Sep 2026
- **Also known as:** GHSA-2m6h-5wp5-qp66, GHSA-pvrx-3g7m-fpgv

## What is CVE-2026-103088?

CVE-2026-103088 is a high-severity path traversal vulnerability in jknack handlebars.java, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Handlebars.java before 4.5.5 allows directory traversal. In handlebars-springmvc 4.5.3 and 4.5.4, the path-containment fix for CVE-2026-63490 validates template locations as raw percent-encoded strings, whereas the template file is opened through a URL handler that percent-decodes the path. In a Spring MVC application with a file: template prefix and a request-derived view name, a percent-encoded traversal such as %2e%2e/ bypasses both the view-resolver check and the loader-side containment and reads files outside the configured template base directory.

Weakness: CWE-24 (Path Traversal: '../filedir')

## Which versions are affected by CVE-2026-103088?


## How do I fix CVE-2026-103088?

No fix has been published for CVE-2026-103088 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-103088 being exploited?

There is no known exploitation of CVE-2026-103088 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-103088 and fix it if it is affected.

What it is: CVE-2026-103088 is a high-severity path traversal vulnerability in jknack handlebars.java, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-103088 in the wild and no public exploit code.

Affected product: jknack handlebars.java. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-103088/ (Markdown: https://insights.sbomify.com/CVE-2026-103088/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-103088
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-103088
- OSV: https://osv.dev/vulnerability/CVE-2026-103088

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-103088/
Summaries are generated and may contain mistakes; the official description above is the record.