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

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.

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
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Repository advisory
Open repository advisory ↗
Source code
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Published (advisory)
2021-11-15 17:54:01 UTC
Updated
2023-05-04 19:51:19 UTC
GitHub reviewed
2021-11-15 17:53:35 UTC
NVD published
2021-11-15

EPSS Score

Score Percentile
0.20% 42.03%

CVSS Scores

Base score Version Severity Vector
6.2 3.1
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:L/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.

Identifiers

CWEs

CWE id Name
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
CWE-327 Use of a Broken or Risky Cryptographic Algorithm
CWE-565 Reliance on Cookies without Validation and Integrity Checking

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
rubygems rails_multisite < 4.0.0 4.0.0

References

cvelogic Threat Intelligence