CVE-2026-49473
@cedar-policy/authorization-for-expressjs has an authorization bypass via query string manipulation
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
@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.
Timeline
ID reserved
By GitHub_M
- 2 months later
· 2 months later
Published
- 1 day later
· 1 day later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Deferred | 3.1 | High8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.47% · top 59% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.8.
Weakness
Affected products
cedar-policy · authorization-for-expressjs
- affected < 0.3.0
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- npm@cedar-policy/authorization-for-expressjsGHSA-g4w6-vmgf-xqvx (opens in a new tab)
References (2)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-g4w6-vmgf-xqvx (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-49473)Record last updated .