CVE-2020-15240 — Regression in omniauth-auth0 — CVE Details
HIGH
Regression in JWT Signature Validation
Published November 3, 2020Updated July 8, 2026Source: osv
Summary
### Overview
Versions after and including `2.3.0` are improperly validating the JWT token signature when using the `JWTValidator.verify` method. Improper validation of the JWT token signature when not using the default Authorization Code Flow can allow an attacker to bypass authentication and authorization.
### Am I affected?
You are affected by this vulnerability if all of the following conditions apply:
- You are using `omniauth-auth0`.
- You are using `JWTValidator.verify` method directly OR you are not authenticating using the SDK’s default Authorization Code Flow.
### How to fix that?
Upgrade to version `2.4.1`.
### Will this update impact my users?
The fix provided in this version will not affect your users.
Advisory Timeline
- First published November 3, 2020 (2169 days ago).
- Last revised July 8, 2026 — 2073 days after initial publication.
Remediation
Upgrade to the fixed version using your package manager.
Bundler
Update omniauth-auth0 to 2.4.1 or latergem install omniauth-auth0 -v 2.4.1
After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.
Affected Packages (1)
Affects 1 ecosystem: rubygems (1).
| Package | Ecosystem | Affected | Fixed In |
|---|---|---|---|
| omniauth-auth0 | rubygems | 2.3.0, 2.3.1, 2.4.0 | 2.4.1 |
Vulnerability Classification
Common Weakness Enumeration (CWE) identifiers for this vulnerability type.
CVSS Score Breakdown
What the CVSS (Common Vulnerability Scoring System) 7.4 score means for each attack dimension.
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
References
- https://github.com/auth0/omniauth-auth0/security/advisories/GHSA-58r4-h6v8-jcvmWEB
- https://nvd.nist.gov/vuln/detail/CVE-2020-15240ADVISORY
- https://github.com/auth0/omniauth-auth0/commit/fd3a14f4ccdfbc515d1121d6378ff88bf55a7a7aWEB
- https://github.com/auth0/omniauth-auth0PACKAGE
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/omniauth-auth0/CVE-2020-15240.ymlWEB
- https://rubygems.org/gems/omniauth-auth0WEB
Frequently Asked Questions
- What is CVE-2020-15240?
- Regression in JWT Signature Validation This vulnerability has been assigned a severity rating of HIGH (CVSS score: 7.4/10).
- How do I check if my project is affected by CVE-2020-15240?
- CVE-2020-15240 affects omniauth-auth0. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2020-15240 and 200,000+ other known vulnerabilities.
Severity & Exploitability
CVSS Score
7.4
High exploitability or significant impact. Prioritize remediation within days.
Also Known As
GHSA-58r4-h6v8-jcvm
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