CVE-2021-22885: Action Pack contains Information Disclosure / Unintended Method Execution vulnerability

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 4.1% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-05-27 · updated 2026-06-17
Weakness: CWE-209

Description

A possible information disclosure / unintended method execution vulnerability in Action Pack >= 2.0.0 when using the `redirect_to` or `polymorphic_url`helper with untrusted user input.

Affected products

Debian Linux: 10.0
rubyonrails Actionpack Page-Caching: all versions
Ruby on Rails: from 5.2.0.0 before 5.2.4.6; from 6.0.0.0 before 6.0.3.7; from 6.1.0.0 before 6.1.3.1 — fixed in 5.2.4.6, 6.0.3.7, 6.1.3.1
Rubygems Actionpack: from 6.0.0 before 6.0.3.7; from 6.1.0 before 6.1.3.2; from 5.2.5 before 5.2.6; from 2.0.0 before 5.2.4.6; 6.0.0, 6.0.1, 6.0.1.rc1, 6.0.2, 6.0.2.1, 6.0.2.2 (+337) — fixed in 6.0.3.7, 6.1.3.2, 5.2.6, 5.2.4.6

How to fix

Upgrade to a fixed version: Ruby on Rails 5.2.4.6, 6.0.3.7, 6.1.3.1; Rubygems Actionpack 6.0.3.7, 6.1.3.2, 5.2.6, 5.2.4.6. Check the vendor advisory for mitigations.

References

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