Summary
CedarJava has type confusion vulnerability
CedarJava is an open source Java implementation of the Cedar policy language, used for fine-grained authorization decisions. Under certain circumstances, improper input handling could allow type confusion across the Java-Rust FFI boundary.
Impacted versions:
< 4.9
Workarounds
Enable schema-based request validation to catch type mismatches. Validate that user-controlled data does not contain reserved keys (__entity or __extn) before building CedarMap objects.
References
If you have any questions or comments about this advisory, we ask that you contact us directly via email to [email protected]. Please do not create a public GitHub issue.
Impact
Record-to-Entity type confusion across the Java-Rust FFI boundary
CedarJava sends authorization requests to the Rust cedar-policy evaluator as JSON. The JSON protocol reserves magic single-key object shapes (__entity and __extn) for entity references and extension values. When serializing a CedarMap, there is no validation preventing these reserved keys from being used. If an integrating service builds a CedarMap from caller-supplied key/value data (such as request headers, user-defined metadata, or resource tags), an actor who controls those keys could cause the Rust evaluator to interpret a record as an entity reference.
This issue requires the integrating service to build a CedarMap where the an actor controls the keys, and a policy must reference that value in a when/unless clause.
An object is accessed using a type that is incompatible with its actual type, causing the runtime to interpret memory incorrectly. Typical impact: memory safety violations, unexpected behavior, or code execution.
CVE-2026-55772 has a CVSS score of 8.8 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.3.6, 3.4.1, 4.9.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Addressed in CedarJava version 2.3.6, 3.4.1, and 4.9 and above. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.
Frequently Asked Questions
- What is CVE-2026-55772? CVE-2026-55772 is a high-severity type confusion vulnerability in com.cedarpolicy:cedar-java (maven), affecting versions < 2.3.6. It is fixed in 2.3.6, 3.4.1, 4.9.0. An object is accessed using a type that is incompatible with its actual type, causing the runtime to interpret memory incorrectly.
- How severe is CVE-2026-55772? CVE-2026-55772 has a CVSS score of 8.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of com.cedarpolicy:cedar-java are affected by CVE-2026-55772? com.cedarpolicy:cedar-java (maven) versions < 2.3.6 is affected.
- Is there a fix for CVE-2026-55772? Yes. CVE-2026-55772 is fixed in 2.3.6, 3.4.1, 4.9.0. Upgrade to this version or later.
- Is CVE-2026-55772 exploitable, and should I be worried? Whether CVE-2026-55772 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-55772 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-55772?
- Upgrade
com.cedarpolicy:cedar-javato 2.3.6 or later - Upgrade
com.cedarpolicy:cedar-javato 3.4.1 or later - Upgrade
com.cedarpolicy:cedar-javato 4.9.0 or later
- Upgrade