Staging Environment: Content and features may be unstable or change without notice.
Advisory details: ruby_advisory_db / gems/actionpack/CVE-2020-8166
Advisory ID ruby_advisory_db/gems/actionpack/CVE-2020-8166
Aliases CVE-2020-8166
GHSA-jp5v-5gx4-jmj9
Summary Ability to forge per-form CSRF tokens given a global CSRF token It is possible to 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. Versions Affected: rails < 5.2.5, rails < 6.0.4 Not affected: Applications without existing HTML injection vulnerabilities. Fixed Versions: rails >= 5.2.4.3, rails >= 6.0.3.1 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.
Status Published
Exploitability 0.5
Weighted Severity 0.0
Risk
Affected and Fixed Packages Package Details
Introduced and Fixed Package Commit Patches Package Commit Patches Details
Weaknesses (0)
There are no known CWE.
System Score Found at
cvssv3 4.3
Reference id Reference type URL
https://groups.google.com/forum/#!topic/rubyonrails-security/NOjKiGeXUgw

No exploits are available.

No EPSS data available for this advisory.

Patch URL
There are no known patches.

There are no known vectors.

Vector: SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2026-04-28T15:45:41Z/

Decision: Track

Source URL: https://github.com/cisagov/vulnrichment/blob/develop/2020/8xxx/CVE-2020-8166.json

Source Advisory: vulnrichment/CVE-2020-8166

View SSVC decision tree 
[{'Exploitation': 'poc'},
 {'Automatable': 'no'},
 {'Technical Impact': 'partial'},
 {'Mission Prevalence': 'minimal'},
 {'Public Well-being Impact': 'material'},
 {'Mission & Well-being': 'medium'}]