cedar-policy Authorization for Expressjs up to 0.2.x improper authorization

Summaryinfo

A vulnerability was found in cedar-policy Authorization for Expressjs up to 0.2.x. It has been classified as problematic. Impacted is an unknown function. This manipulation causes improper authorization. This vulnerability is tracked as CVE-2026-49473. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability has been found in cedar-policy Authorization for Expressjs up to 0.2.x and classified as problematic. Affected by this vulnerability is an unknown code block. The manipulation with an unknown input leads to a improper authorization vulnerability. The CWE definition for the vulnerability is CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. As an impact it is known to affect confidentiality. The summary by CVE is:

@cedar-policy/authorization-for-expressjs is an open-source Express.js middleware that integrates Cedar authorization into Express applications by mapping HTTP requests to Cedar actions and evaluating authorization policies before allowing requests to proceed. Versions prior to 0.3.0 have an issue where, under certain circumstances, the middleware matches incoming requests against Cedar action mappings using req.originalUrl, which includes the query string, while Express routes requests using only the path component. The middleware uses req.originalUrl to match incoming requests against Cedar action mappings. In Express, req.originalUrl includes the query string, while route matching uses only the path. This creates a divergence between what Cedar authorizes and what Express executes. When an application defines separate actions for overlapping path prefixes with different authorization requirements (for example, GET /users for listing all users with admin-only access, and GET /users/{id} for retrieving a single user with any authenticated user access), an actor can append a query string to bypass the more restrictive policy. Sending GET /users/?x=1 causes the middleware to match against /users/{id} (with id parameter set to ?x=1) and evaluate the less restrictive action, while Express routes the request to the /users list handler. This allows inappropriate access to the more restrictive endpoint. This issue has been addressed in version 0.30. Some workarounds are available. Validate and sanitize incoming request paths before they reach the authorization middleware. Ensure that applications do not rely solely on the middleware for authorization when defining multiple actions on overlapping path prefixes with different permission levels.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-49473 since 05/30/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1548.002 for this issue.

Upgrading to version 0.3.0 eliminates this vulnerability.

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Productinfo

Vendor

• cedar-policy

Name

• Authorization for Expressjs

Version

• 0.1
• 0.2

CPE 2.3info

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CPE 2.2info

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