CVE-2021-39197 Detail

Current Description

better_errors is an open source replacement for the standard Rails error page with more information rich error pages. It is also usable outside of Rails in any Rack app as Rack middleware. better_errors prior to 2.8.0 did not implement CSRF protection for its internal requests. It also did not enforce the correct "Content-Type" header for these requests, which allowed a cross-origin "simple request" to be made without CORS protection. These together left an application with better_errors enabled open to cross-origin attacks. As a developer tool, better_errors documentation strongly recommends addition only to the `development` bundle group, so this vulnerability should only affect development environments. Please ensure that your project limits better_errors to the `development` group (or the non-Rails equivalent). Starting with release 2.8.x, CSRF protection is enforced. It is recommended that you upgrade to the latest release, or minimally to "~> 2.8.3". There are no known workarounds to mitigate the risk of using older releases of better_errors.


View Analysis Description

Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  8.8 HIGH
Vector:  CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
Base Score:  6.3 MEDIUM
Vector:  CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/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: It is possible that the NVD CVSS may not match that of the CNA. The most common reason for this is that publicly available information does not provide sufficient detail or that information simply was not available at the time the CVSS vector string was assigned.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/BetterErrors/better_errors/commit/8e8e796bfbde4aa088741823c8a3fc6df2089bb0 Patch  Third Party Advisory 
https://github.com/BetterErrors/better_errors/discussions/507 Third Party Advisory 
https://github.com/BetterErrors/better_errors/pull/474 Patch  Third Party Advisory 
https://github.com/BetterErrors/better_errors/security/advisories/GHSA-w3j4-76qw-wwjm Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-352 Cross-Site Request Forgery (CSRF) Provider acceptance level GitHub, Inc.  

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Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-39197
NVD Published Date:
09/07/2021
NVD Last Modified:
09/14/2021
Source:
GitHub, Inc.