U.S. flag   An official website of the United States government
Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock (Dot gov) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

NOTICE UPDATE

NIST has updated the NVD program announcement page with additional information regarding recent concerns and the temporary delays in enrichment efforts.

CVE-2021-21276 Detail

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.


Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score matches with CNA score
CNA:  GitHub, Inc.
Base Score:  9.3 CRITICAL
Vector:  CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: The NVD and the CNA have provided the same score. When this occurs only the CNA information is displayed, but the Acceptance Level icon for the CNA is given a checkmark to signify NVD concurrence.

References to Advisories, Solutions, and Tools

By selecting these links, you will be leaving NIST webspace. We have provided these links to other web sites because they may have information that would be of interest to you. No inferences should be drawn on account of other sites being referenced, or not, from this page. There may be other web sites that are more appropriate for your purpose. NIST does not necessarily endorse the views expressed, or concur with the facts presented on these sites. Further, NIST does not endorse any commercial products that may be mentioned on these sites. Please address comments about this page to nvd@nist.gov.

Hyperlink Resource
http://packetstormsecurity.com/files/171743/POLR-URL-2.3.0-Shortener-Admin-Takeover.html
https://github.com/cydrobolt/polr/commit/b1981709908caf6069b4a29dad3b6739c322c675 Patch  Third Party Advisory 
https://github.com/cydrobolt/polr/releases/tag/2.3.0 Release Notes  Third Party Advisory 
https://github.com/cydrobolt/polr/security/advisories/GHSA-vg6w-8w9v-xxqc Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
NVD-CWE-Other Other cwe source acceptance level NIST  
CWE-863 Incorrect Authorization Provider acceptance level GitHub, Inc.  

Known Affected Software Configurations Switch to CPE 2.2

CPEs loading, please wait.

Denotes Vulnerable Software
Are we missing a CPE here? Please let us know.

Change History

3 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-21276
NVD Published Date:
02/01/2021
NVD Last Modified:
04/06/2023
Source:
GitHub, Inc.