Vulnerability Description
Polr is an open source URL shortener. in Polr before version 2.3.0, a vulnerability in the setup process allows attackers to gain admin access to site instances, even if they do not possess an existing account. This vulnerability exists regardless of users' settings. If an attacker crafts a request with specific cookie headers to the /setup/finish endpoint, they may be able to obtain admin privileges on the instance. This is caused by a loose comparison (==) in SetupController that is susceptible to attack. The project has been patched to ensure that a strict comparison (===) is used to verify the setup key, and that /setup/finish verifies that no users table exists before performing any migrations or provisioning any new accounts. This is fixed in version 2.3.0. Users can patch this vulnerability without upgrading by adding abort(404) to the very first line of finishSetup in SetupController.php.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Polrproject | Polr | < 2.3.0 |
Related Weaknesses (CWE)
References
- http://packetstormsecurity.com/files/171743/POLR-URL-2.3.0-Shortener-Admin-Takeo
- https://github.com/cydrobolt/polr/commit/b1981709908caf6069b4a29dad3b6739c322c67PatchThird Party Advisory
- https://github.com/cydrobolt/polr/releases/tag/2.3.0Release NotesThird Party Advisory
- https://github.com/cydrobolt/polr/security/advisories/GHSA-vg6w-8w9v-xxqcThird Party Advisory
- http://packetstormsecurity.com/files/171743/POLR-URL-2.3.0-Shortener-Admin-Takeo
- https://github.com/cydrobolt/polr/commit/b1981709908caf6069b4a29dad3b6739c322c67PatchThird Party Advisory
- https://github.com/cydrobolt/polr/releases/tag/2.3.0Release NotesThird Party Advisory
- https://github.com/cydrobolt/polr/security/advisories/GHSA-vg6w-8w9v-xxqcThird Party Advisory
FAQ
What is CVE-2021-21276?
CVE-2021-21276 is a vulnerability with a CVSS score of 9.3 (CRITICAL). Polr is an open source URL shortener. in Polr before version 2.3.0, a vulnerability in the setup process allows attackers to gain admin access to site instances, even if they do not possess an existin...
How severe is CVE-2021-21276?
CVE-2021-21276 has been rated CRITICAL with a CVSS base score of 9.3/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2021-21276?
Check the references section above for vendor advisories and patch information. Affected products include: Polrproject Polr.