Vulnerability Description
AssertJ provides Fluent testing assertions for Java and the Java Virtual Machine (JVM). Starting in version 1.4.0 and prior to version 3.27.7, an XML External Entity (XXE) vulnerability exists in `org.assertj.core.util.xml.XmlStringPrettyFormatter`: the `toXmlDocument(String)` method initializes `DocumentBuilderFactory` with default settings, without disabling DTDs or external entities. This formatter is used by the `isXmlEqualTo(CharSequence)` assertion for `CharSequence` values. An application is vulnerable only when it uses untrusted XML input with either `isXmlEqualTo(CharSequence)` from `org.assertj.core.api.AbstractCharSequenceAssert` or `xmlPrettyFormat(String)` from `org.assertj.core.util.xml.XmlStringPrettyFormatter`. If untrusted XML input is processed by tone of these methods, an attacker couldnread arbitrary local files via `file://` URIs (e.g., `/etc/passwd`, application configuration files); perform Server-Side Request Forgery (SSRF) via HTTP/HTTPS URIs, and/or cause Denial of Service via "Billion Laughs" entity expansion attacks. `isXmlEqualTo(CharSequence)` has been deprecated in favor of XMLUnit in version 3.18.0 and will be removed in version 4.0. Users of affected versions should, in order of preference: replace `isXmlEqualTo(CharSequence)` with XMLUnit, upgrade to version 3.27.7, or avoid using `isXmlEqualTo(CharSequence)` or `XmlStringPrettyFormatter` with untrusted input. `XmlStringPrettyFormatter` has historically been considered a utility for `isXmlEqualTo(CharSequence)` rather than a feature for AssertJ users, so it is deprecated in version 3.27.7 and removed in version 4.0, with no replacement.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Assertj | Assertj | >= 1.4.0, < 3.27.7 |
Related Weaknesses (CWE)
References
- https://cheatsheetseries.owasp.org/cheatsheets/XML_External_Entity_Prevention_ChTechnical Description
- https://github.com/assertj/assertj/commit/85ca7eb6609bb179c043b85ae7d290523b1ba7Patch
- https://github.com/assertj/assertj/releases/tag/assertj-build-3.27.7ProductRelease Notes
- https://github.com/assertj/assertj/security/advisories/GHSA-rqfh-9r24-8c9rMitigationVendor Advisory
FAQ
What is CVE-2026-24400?
CVE-2026-24400 is a vulnerability with a CVSS score of 9.1 (CRITICAL). AssertJ provides Fluent testing assertions for Java and the Java Virtual Machine (JVM). Starting in version 1.4.0 and prior to version 3.27.7, an XML External Entity (XXE) vulnerability exists in `org...
How severe is CVE-2026-24400?
CVE-2026-24400 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-24400?
Check the references section above for vendor advisories and patch information. Affected products include: Assertj Assertj.