CVE-2026-40155 Vulnerability Analysis & Exploit Details

CVE-2026-40155
Vulnerability Scoring

5.4
/10
Significant Risk

Security assessments indicate that CVE-2026-40155 presents a notable risk, potentially requiring prompt mitigation.

Attack Complexity Details

  • Attack Complexity: High
    Exploits require significant effort and special conditions.
  • Attack Vector: Network
    Vulnerability is exploitable over a network without physical access.
  • Privileges Required: Low
    Some privileges are necessary to exploit the vulnerability.
  • Scope: Unchanged
    Exploit remains within the originally vulnerable component.
  • User Interaction: Required
    User interaction is necessary for successful exploitation.

CVE-2026-40155 Details

Status: Analyzed

Last updated: 🕢 27 Apr 2026, 19:41 UTC
Originally published on: 🕘 17 Apr 2026, 21:16 UTC

Time between publication and last update: 9 days

CVSS Release: version 3

CVSS3 Source

security-advisories@github.com

CVSS3 Type

Secondary

CVSS3 Vector

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

CVE-2026-40155 Vulnerability Summary

CVE-2026-40155: The Auth0 Next.js SDK is a library for implementing user authentication in Next.js applications. In versions 4.12.0 through 4.17.1, simultaneous requests that trigger a nonce retry may cause the proxy cache fetcher to perform improper lookups for the token request results. Users are affected if their project uses both the vulnerable versions and the proxy handler /me/* and /my-org/* with DPoP enabled. This issue has been fixed in version 4.18.0.

Assessing the Risk of CVE-2026-40155

Access Complexity Graph

The exploitability of CVE-2026-40155 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-40155

This vulnerability, CVE-2026-40155, requires a high level of attack complexity and low privileges, making it difficult but not impossible to exploit. Organizations should ensure robust security configurations to mitigate risks.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-40155, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-40155, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: High
    Exploiting CVE-2026-40155 can result in unauthorized access to sensitive data, severely compromising data privacy.
  • Integrity: Low
    Exploiting CVE-2026-40155 may cause minor changes to data without severely impacting its accuracy.
  • Availability: None
    CVE-2026-40155 does not impact system availability.

CVE-2026-40155 References

External References

CWE Common Weakness Enumeration

CWE-863

Vulnerable Configurations

  • cpe:2.3:a:auth0:nextjs-auth0:4.12.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:auth0:nextjs-auth0:4.12.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:auth0:nextjs-auth0:4.12.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:auth0:nextjs-auth0:4.12.1:*:*:*:*:node.js:*:*
  • cpe:2.3:a:auth0:nextjs-auth0:4.13.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:auth0:nextjs-auth0:4.13.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:auth0:nextjs-auth0:4.13.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:auth0:nextjs-auth0:4.13.1:*:*:*:*:node.js:*:*
  • cpe:2.3:a:auth0:nextjs-auth0:4.13.2:*:*:*:*:node.js:*:*
    cpe:2.3:a:auth0:nextjs-auth0:4.13.2:*:*:*:*:node.js:*:*
  • cpe:2.3:a:auth0:nextjs-auth0:4.13.3:*:*:*:*:node.js:*:*
    cpe:2.3:a:auth0:nextjs-auth0:4.13.3:*:*:*:*:node.js:*:*
  • cpe:2.3:a:auth0:nextjs-auth0:4.14.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:auth0:nextjs-auth0:4.14.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:auth0:nextjs-auth0:4.14.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:auth0:nextjs-auth0:4.14.1:*:*:*:*:node.js:*:*
  • cpe:2.3:a:auth0:nextjs-auth0:4.15.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:auth0:nextjs-auth0:4.15.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:auth0:nextjs-auth0:4.16.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:auth0:nextjs-auth0:4.16.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:auth0:nextjs-auth0:4.16.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:auth0:nextjs-auth0:4.16.1:*:*:*:*:node.js:*:*
  • cpe:2.3:a:auth0:nextjs-auth0:4.16.2:*:*:*:*:node.js:*:*
    cpe:2.3:a:auth0:nextjs-auth0:4.16.2:*:*:*:*:node.js:*:*
  • cpe:2.3:a:auth0:nextjs-auth0:4.17.0:*:*:*:*:node.js:*:*
    cpe:2.3:a:auth0:nextjs-auth0:4.17.0:*:*:*:*:node.js:*:*
  • cpe:2.3:a:auth0:nextjs-auth0:4.17.1:*:*:*:*:node.js:*:*
    cpe:2.3:a:auth0:nextjs-auth0:4.17.1:*:*:*:*:node.js:*:*

Protect Your Infrastructure against CVE-2026-40155: Combat Critical CVE Threats

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