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Ability to forge per-form CSRF tokens in Rails

Moderate severity GitHub Reviewed Published May 26, 2020 to the GitHub Advisory Database • Updated Aug 17, 2023

Package

bundler actionpack (RubyGems)

Affected versions

>= 5.0.0, <= 5.2.4.2
>= 6.0.0, <= 6.0.3

Patched versions

5.2.4.3
6.0.3.1

Description

It is possible to, given a global CSRF token such as the one present in the authenticity_token meta tag, forge a per-form CSRF token for any action for that session.

Impact

Given the ability to extract the global CSRF token, an attacker would be able to construct a per-form CSRF token for that session.

Workarounds

This is a low-severity security issue. As such, no workaround is necessarily until such time as the application can be upgraded.

References

Reviewed May 26, 2020
Published to the GitHub Advisory Database May 26, 2020
Last updated Aug 17, 2023

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

EPSS score

0.219%
(61st percentile)

Weaknesses

CVE ID

CVE-2020-8166

GHSA ID

GHSA-jp5v-5gx4-jmj9

Source code

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