CVE-2026-23734: Xwiki commons classloader api Remote Code Execution Vulnerability

CRITICAL
Advisory Identifier: GHSA-xq3r-2qv5-vqqm
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CWE-23
Published
Advisory Summary

CVE-2026-23734 is a CRITICAL remote code execution vulnerability (CWE-23: Relative Path Traversal) affecting Xwiki commons classloader api libraries in the Maven ecosystem. The issue involves xwiki platform has path traversal via resources parameter in ssx and jsx endpoints when using leading slash. Remediation is available by upgrading affected packages to version 16.10.17, 17.4.9, 17.10.3, 18.1.0-rc-1.

CVE-2026-23734 at a Glance

CVE Identifier CVE-2026-23734
GHSA Identifier GHSA-xq3r-2qv5-vqqm
Severity CRITICAL
CVSS v3.1 Base Score N/A
CWE Classification CWE-23: Relative Path Traversal
Affected Product Xwiki commons classloader api
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2026-23734

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

org.xwiki.commons:xwiki-commons-classloader-api fixed: 16.10.17 
<dependency>
    <groupId>org.xwiki.commons</groupId>
    <artifactId>xwiki-commons-classloader-api</artifactId>
    <version>16.10.17</version>
</dependency>
org.xwiki.commons:xwiki-commons-classloader-api fixed: 17.4.9 
<dependency>
    <groupId>org.xwiki.commons</groupId>
    <artifactId>xwiki-commons-classloader-api</artifactId>
    <version>17.4.9</version>
</dependency>
org.xwiki.commons:xwiki-commons-classloader-api fixed: 17.10.3 
<dependency>
    <groupId>org.xwiki.commons</groupId>
    <artifactId>xwiki-commons-classloader-api</artifactId>
    <version>17.10.3</version>
</dependency>
org.xwiki.commons:xwiki-commons-classloader-api fixed: 18.1.0-rc-1 
<dependency>
    <groupId>org.xwiki.commons</groupId>
    <artifactId>xwiki-commons-classloader-api</artifactId>
    <version>18.1.0-rc-1</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=org.xwiki.commons

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-23734, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.xwiki.commons

Analyze the terminal output to locate any version of Xwiki commons classloader api in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 16.10.17), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.xwiki.commons 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-23: Relative Path Traversal, where the product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as ".." that can resolve to a location that is outside of that directory. In Xwiki commons classloader api, 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 It's possible to get access and read configuration files by using URLs such as `http://localhost:8080/bin/ssx/Main/WebHome?resource=/../../WEB-INF/xwiki.cfg&minify=false`. This can apparently be reproduced on Tomcat instances. ### Patches This has been patched in 18.0.0-rc-1, 17.10.3, 17.4.9, 16.10.17. ### Workarounds There is no known workaround, other than upgrading XWiki. ### References * https://jira.xwiki.org/browse/XCOMMONS-3547 * https://github.com/xwiki/xwiki-commons/commit/a979cafd89f6a9c9c0b9ab19744d672df64429bf ### For more information If you have any questions or comments about this advisory: * Open an issue in [Jira XWiki.org](https://jira.xwiki.org/) * Email us at [Security Mailing List](mailto:security@xwiki.org) ### Attribution The vulnerability was reported by Michał Kołek.

CVE-2026-23734 Affected Xwiki commons classloader api Versions

4 component(s)
Fixed Versions:
16.10.1717.4.917.10.318.1.0-rc-1
Product / Package Ecosystem Affected Versions Fixed Version
org.xwiki.commons:xwiki-commons-classloader-api
maven/org.xwiki.commons/xwiki-commons-classloader-api
Maven
≥ 4.2-milestone-2
< 16.10.17
16.10.17
org.xwiki.commons:xwiki-commons-classloader-api
maven/org.xwiki.commons/xwiki-commons-classloader-api
Maven
≥ 17.0.0-rc-1
< 17.4.9
17.4.9
org.xwiki.commons:xwiki-commons-classloader-api
maven/org.xwiki.commons/xwiki-commons-classloader-api
Maven
≥ 17.5.0
< 17.10.3
17.10.3
org.xwiki.commons:xwiki-commons-classloader-api
maven/org.xwiki.commons/xwiki-commons-classloader-api
Maven
≥ 18.0.0-rc-1
< 18.1.0-rc-1
18.1.0-rc-1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/xwiki/xwiki-commons/security/advisories/GHSA-xq3r-2qv5-vqqm
NVD — CVE-2026-23734 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-23734
Security Fix Commit FIX COMMIT
https://github.com/xwiki/xwiki-commons/commit/a979cafd89f6a9c9c0b9ab19744d672df64429bf
Xwiki commons classloader api Source Repository REPOSITORY
https://github.com/xwiki/xwiki-commons
jira.xwiki.org/browse/xcommons-354... WEB
https://jira.xwiki.org/browse/XCOMMONS-3547

Frequently Asked Questions

What is CVE-2026-23734?
CVE-2026-23734 is a security vulnerability in Xwiki commons classloader api involving XWiki Platform has path traversal via resources parameter in ssx and jsx endpoints when using leading slash under CWE-23: Relative Path Traversal.
Which Xwiki commons classloader api versions are affected?
Affected versions include releases prior to 16.10.17, 17.4.9, 17.10.3, 18.1.0-rc-1 across affected packages: org.xwiki.commons:xwiki-commons-classloader-api.
What version fixes CVE-2026-23734?
Upgrading to 16.10.17, 17.4.9, 17.10.3, 18.1.0-rc-1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is xwiki-commons-classloader-api affected?
Yes, org.xwiki.commons:xwiki-commons-classloader-api is affected in releases prior to 16.10.17, 17.4.9, 17.10.3, 18.1.0-rc-1. Upgrade your dependency to 16.10.17, 17.4.9, 17.10.3, 18.1.0-rc-1 or later.
What CWE is associated with CVE-2026-23734?
CVE-2026-23734 is classified under CWE-23: Relative Path Traversal (The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as ".." that can resolve to a location that is outside of that directory.).
How can I check Maven dependencies for CVE-2026-23734?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.xwiki.commons'. 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-xq3r-2qv5-vqqm",
  "modified" : "2026-05-26T17:16:40Z",
  "published" : "2026-05-26T17:16:40Z",
  "aliases" : [ "CVE-2026-23734" ],
  "summary" : "XWiki Platform has path traversal via resources parameter in ssx and jsx endpoints when using leading slash",
  "details" : "### Impact\n\nIt's possible to get access and read configuration files by using URLs such as `http://localhost:8080/bin/ssx/Main/WebHome?resource=/../../WEB-INF/xwiki.cfg&minify=false`.\n\nThis can apparently be reproduced on Tomcat instances.\n\n### Patches\n\nThis has been patched in 18.0.0-rc-1, 17.10.3, 17.4.9, 16.10.17.\n\n### Workarounds\n\nThere is no known workaround, other than upgrading XWiki.\n\n### References\n\n* https://jira.xwiki.org/browse/XCOMMONS-3547\n* https://github.com/xwiki/xwiki-commons/commit/a979cafd89f6a9c9c0b9ab19744d672df64429bf\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n* Open an issue in [Jira XWiki.org](https://jira.xwiki.org/)\n* Email us at [Security Mailing List](mailto:security@xwiki.org)\n\n### Attribution\n\nThe vulnerability was reported by Michał Kołek.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.xwiki.commons:xwiki-commons-classloader-api"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.2-milestone-2"
      }, {
        "fixed" : "16.10.17"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.xwiki.commons:xwiki-commons-classloader-api"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "17.0.0-rc-1"
      }, {
        "fixed" : "17.4.9"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.xwiki.commons:xwiki-commons-classloader-api"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "17.5.0"
      }, {
        "fixed" : "17.10.3"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.xwiki.commons:xwiki-commons-classloader-api"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "18.0.0-rc-1"
      }, {
        "fixed" : "18.1.0-rc-1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/xwiki/xwiki-commons/security/advisories/GHSA-xq3r-2qv5-vqqm"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-23734"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/xwiki/xwiki-commons/commit/a979cafd89f6a9c9c0b9ab19744d672df64429bf"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/xwiki/xwiki-commons"
  }, {
    "type" : "WEB",
    "url" : "https://jira.xwiki.org/browse/XCOMMONS-3547"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-23" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-26T17:16:40Z",
    "nvd_published_at" : "2026-05-20T20:16:36Z"
  }
}