Rails Multisite secure/signed cookies share secrets between sites in a multi-site application

GHSA-844m-cpr9-jcmh · CVE-2021-41263

Published Nov 15, 2021 · Modified Mar 13, 2026

Description

Impact

This vulnerability impacts any Rails applications using rails_multisite alongside Rails' signed/encrypted cookies. Depending on how the application makes use of these cookies, it may be possible for an attacker to re-use cookies on different 'sites' within a multi-site Rails application.

Patches

The issue has been patched in v4 of the rails_multisite gem. Note that this upgrade will invalidate all previous signed/encrypted cookies. The impact of this invalidation will vary based on the application architecture.

References

WEB https://github.com/discourse/rails_multisite/security/advisories/GHSA-844m-cpr9-jcmh
ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2021-41263
WEB https://github.com/discourse/rails_multisite/commit/c6785cdb5c9277dd2c5ac8d55180dd1ece440ed0
PACKAGE https://github.com/discourse/rails_multisite
WEB https://github.com/rubysec/ruby-advisory-db/blob/master/gems/rails_multisite/CVE-2021-41263.yml

Ready to move

Start Securing

Start for Free Get Demo

Free, no credit card | First findings in minutes