CVE-2026-55760: Handlebars Path Traversal Vulnerability

HIGH
Advisory Identifier: GHSA-r4gv-qr8j-p3pg
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CVSS 7.5
CWE-22
Published
Advisory Summary

CVE-2026-55760 is a HIGH (CVSS 7.5) path traversal vulnerability (CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')) affecting Handlebars libraries in the Maven ecosystem. The issue involves handlebars.java filetemplateloader path traversal. Remediation is available by upgrading affected packages to version 4.5.2.

CVE-2026-55760 at a Glance

CVE Identifier CVE-2026-55760
GHSA Identifier GHSA-r4gv-qr8j-p3pg
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Affected Product Handlebars
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2026-55760

To remediate this vulnerability, upgrade all affected Handlebars dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

com.github.jknack:handlebars fixed: 4.5.2 
<dependency>
    <groupId>com.github.jknack</groupId>
    <artifactId>handlebars</artifactId>
    <version>4.5.2</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree -Dincludes=com.github.jknack

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-55760, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=com.github.jknack

Analyze the terminal output to locate any version of Handlebars in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.5.2), your application is affected.

Note: The mvn dependency:tree -Dincludes=com.github.jknack command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), where the product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. In Handlebars, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact Any application that passes user-controlled input to Handlebars.compile() using a FileTemplateLoader (or ClassPathTemplateLoader) is vulnerable to arbitrary file read. This is a realistic attack surface for web applications that use template names from URL path parameters, request parameters, or other user-controlled sources. ### Patches com.github.jknack:handlebars:4.5.2 ### Workarounds Validate template name is derived from user input. ```java if (!file.getPath().startsWith(new File(prefix).getCanonicalPath())) { throw new IOException("Path traversal attempt detected: " + location); } ```

CVE-2026-55760 Affected Handlebars Versions

1 component(s)
Fixed Versions:
4.5.2
Product / Package Ecosystem Affected Versions Fixed Version
com.github.jknack:handlebars
maven/com.github.jknack/handlebars
Maven
< 4.5.2
4.5.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/jknack/handlebars.java/security/advisories/GHSA-r4gv-qr8j-p3pg
Handlebars Source Repository REPOSITORY
https://github.com/jknack/handlebars.java

Frequently Asked Questions

What is CVE-2026-55760?
CVE-2026-55760 is a security vulnerability in Handlebars involving handlebars.java FileTemplateLoader Path Traversal under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal').
Which Handlebars versions are affected?
Affected versions include releases prior to 4.5.2 across affected packages: com.github.jknack:handlebars.
What version fixes CVE-2026-55760?
Upgrading to 4.5.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is handlebars affected?
Yes, com.github.jknack:handlebars is affected in releases prior to 4.5.2. Upgrade your dependency to 4.5.2 or later.
What is the CVSS score of CVE-2026-55760?
CVE-2026-55760 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2026-55760?
CVE-2026-55760 is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.).
How can I check Maven dependencies for CVE-2026-55760?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=com.github.jknack'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-r4gv-qr8j-p3pg",
  "modified" : "2026-06-17T18:42:09Z",
  "published" : "2026-06-17T18:42:09Z",
  "aliases" : [ "CVE-2026-55760" ],
  "summary" : "handlebars.java FileTemplateLoader Path Traversal",
  "details" : "### Impact\nAny application that passes user-controlled input to Handlebars.compile() using a FileTemplateLoader (or ClassPathTemplateLoader) is vulnerable to arbitrary file read. This is a realistic attack surface for web applications that use template names from URL path parameters, request parameters, or other user-controlled sources.\n\n### Patches\ncom.github.jknack:handlebars:4.5.2\n\n### Workarounds\n\nValidate template name is derived from user input. \n\n```java\nif (!file.getPath().startsWith(new File(prefix).getCanonicalPath())) {\n        throw new IOException(\"Path traversal attempt detected: \" + location);\n}\n```",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "com.github.jknack:handlebars"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.5.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/jknack/handlebars.java/security/advisories/GHSA-r4gv-qr8j-p3pg"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/jknack/handlebars.java"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-17T18:42:09Z",
    "nvd_published_at" : null
  }
}