Authentication Bypass in omniauth-auth0 (CVE-2020-15240)
Summary
Authentication bypass in omniauth-auth0 (CVE-2020-15240). Confidential information can be exposed externally. Exploitable via jwt_validator.verify. Mitigation: upgrade to 2.4.1 or later.
Original description
The description as published by the source.
omniauth-auth0 (rubygems) versions >= 2.3.0 and < 2.4.1 improperly validate the JWT token signature when using the jwt_validator.verify method. Improper validation of the JWT token signature can allow an attacker to bypass authentication and authorization. You are affected by this vulnerability if all of the following conditions apply: 1. You are using omniauth-auth0. 2. You are using JWTValidator.verify method directly OR you are not authenticating using the SDK’s default Authorization Code Flow. The issue is patched in version 2.4.1.
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2020-15240 has been found in omniauth-auth0.
Attackers can target a specific entry point like jwt_validator.verify over the network to misuse the product.
Confidential information can be exposed externally.
What to do: upgrade omniauth-auth0 to 2.4.1 or later.
If unsure, ask your IT team or search "omniauth-auth0 CVE-2020-15240" on the vendor's site.
CVE-2020-15240 (omniauth-auth0) — CWE-287
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: jwt_validator.verify / JWTValidator.verify
Patched: 2.4.1 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Authentication bypass (CWE-287) exists in omniauth-auth0. Attackers reach the vulnerable code path via jwt_validator.verify without authentication.
Check the vendor advisory for the affected versions of omniauth-auth0. Attack surface: jwt_validator.verify / JWTValidator.verify.
Severity: ?. Confidential information can be exposed externally.
Update to 2.4.1.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'omniauth-auth0' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'omniauth-auth0' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
omniauth-auth0を grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade omniauth-auth0 to 2.4.1ステージング環境で 2.4.1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- advisory rubygems.org
- package github.com
- patch github.com
- web github.com