CVE-2021-39197

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.

CvssV3 impact

Version

3.1

VectorString

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

AttackVector

NETWORK

AttackComplexity

LOW

PrivilegesRequired

NONE

UserInteraction

REQUIRED

Scope

UNCHANGED

ConfidentialityImpact

HIGH

IntegrityImpact

HIGH

AvailabilityImpact

HIGH

BaseScore

8.8

BaseSeverity

HIGH

CvssV2 impact

AccessComplexity

MEDIUM

ConfidentialityImpact

PARTIAL

AvailabilityImpact

PARTIAL

IntegrityImpact

PARTIAL

BaseScore

6.8

VectorString

AV:N/AC:M/Au:N/C:P/I:P/A:P

Version

2.0

AccessVector

NETWORK

Authentication

NONE