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CVE-2020-15240

22
FAUCET Score

CVE-2020-15240 is a critical authentication bypass vulnerability affecting omniauth-auth0 (rubygems) versions 2.3.0 through 2.4.0, stemming from improper JWT token signature validation when using the jwt_validator.verify method or not utilizing the SDK’s default Authorization Code Flow. With a CVSS score of 9.1 (CRITICAL), this flaw allows unauthenticated attackers to bypass security controls, potentially leading to full compromise of confidentiality and integrity. Despite its severity, there is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion surrounding this vulnerability. Organizations using affected versions should upgrade to 2.4.1 immediately to mitigate the risk.

Impacted Technologies

VendorProductVersion(s)CPE
>= 2.3.0, < 2.4.1CPE matchmatch criteria
cpe:2.3:a:auth0:omniauth-auth0:*:*:*:*:*:ruby:*:*

CVSS Data

CVSS version used by this source: 3.1

7.4HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
Exploitability Score
2.2
Impact Score
5.2
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.80%
Probability of exploitation in next 30 days
EPSS Percentile
52.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0080 is in the 37th percentile among its peer group of 36,862 CVEs.

Social Chatter

No social media mentions found for this CVE.

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
rubygemspatch availablevia ghsa
Product: omniauth-auth0Fixed in: 2.4.1

Vendor Advisories (1)

rubygemsGHSA-58r4-h6v8-jcvmhigh

Regression in JWT Signature Validation

Nov 3, 2020

References

github.com / auth0/omniauth-auth0/commit/fd3a14f4ccdfbc515d1121d6378ff88bf55a7a7a
PatchThird Party Advisory
github.com / auth0/omniauth-auth0/security/advisories/GHSA-58r4-h6v8-jcvm
Third Party Advisory
rubygems.org / gems/omniauth-auth0
ProductVendor Advisory