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8.1
HIGH CVSS 3.1
CVE-2026-92087
@fastify/auth vulnerable to Authorization Bypass via order-dependent evaluation of composed auth
Overview
Description

@fastify/auth is a Fastify plugin that composes multiple authentication and authorization strategies into a single route guard. In versions 5.0.0 through 5.1.0, when strategies are composed with the relation "or" option together with the run "all" option and one entry is a nested array acting as an AND group, the group is evaluated in an order-dependent way: an earlier failing check is silently dropped and the group's result becomes the outcome of its last check. As a result, a request that satisfies only the last member of an AND group, for example an attacker who holds a valid API key but is not an administrator, is authorized instead of rejected, and a related order-dependent bypass affects the mirror configuration where the top-level relation is "and" and a nested group uses "or". The issue is fixed in @fastify/auth 5.1.1, and users should upgrade to 5.1.1 or later. As a workaround, omit the run "all" option where it is not required, order each AND group so its stricter check is evaluated last, or replace nested AND groups with an explicit top-level "and" composition.

Details
INFO

Published Date :

Sept. 16, 2026, 3:18 p.m.

Last Modified :

Sept. 16, 2026, 3:18 p.m.

Remotely Exploit :

No

Source :

ce714d77-add3-4f53-aff5-83d477b104bb
Impact
Affected Products

The following products are affected by CVE-2026-92087 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

: Total Affected Vendor : 0 | Products : 0
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 HIGH ce714d77-add3-4f53-aff5-83d477b104bb
Solution
Upgrade @fastify/auth to 5.1.1 or later to fix the authorization bypass.
  • Upgrade @fastify/auth to version 5.1.1 or later.
  • Omit run "all" option if not needed.
  • Order AND groups with stricter checks last.
  • Replace nested AND groups with explicit top-level AND.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-92087.

URL Resource
https://cna.openjsf.org/security-advisories.html
https://github.com/fastify/fastify-auth/security/advisories/GHSA-7h52-2rwr-m76r
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-92087 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-92087 weaknesses.

CAPEC-1: Accessing Functionality Not Properly Constrained by ACLs Accessing Functionality Not Properly Constrained by ACLs CAPEC-5: Blue Boxing Blue Boxing CAPEC-13: Subverting Environment Variable Values Subverting Environment Variable Values CAPEC-17: Using Malicious Files Using Malicious Files CAPEC-39: Manipulating Opaque Client-based Data Tokens Manipulating Opaque Client-based Data Tokens CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-51: Poison Web Service Registry Poison Web Service Registry CAPEC-59: Session Credential Falsification through Prediction Session Credential Falsification through Prediction CAPEC-60: Reusing Session IDs (aka Session Replay) Reusing Session IDs (aka Session Replay) CAPEC-76: Manipulating Web Input to File System Calls Manipulating Web Input to File System Calls CAPEC-77: Manipulating User-Controlled Variables Manipulating User-Controlled Variables CAPEC-87: Forceful Browsing Forceful Browsing CAPEC-104: Cross Zone Scripting Cross Zone Scripting CAPEC-127: Directory Indexing Directory Indexing CAPEC-402: Bypassing ATA Password Security Bypassing ATA Password Security CAPEC-647: Collect Data from Registries Collect Data from Registries CAPEC-668: Key Negotiation of Bluetooth Attack (KNOB) Key Negotiation of Bluetooth Attack (KNOB) CAPEC-3: Using Leading 'Ghost' Character Sequences to Bypass Input Filters Using Leading 'Ghost' Character Sequences to Bypass Input Filters CAPEC-6: Argument Injection Argument Injection CAPEC-7: Blind SQL Injection Blind SQL Injection CAPEC-8: Buffer Overflow in an API Call Buffer Overflow in an API Call CAPEC-9: Buffer Overflow in Local Command-Line Utilities Buffer Overflow in Local Command-Line Utilities CAPEC-10: Buffer Overflow via Environment Variables Buffer Overflow via Environment Variables CAPEC-14: Client-side Injection-induced Buffer Overflow Client-side Injection-induced Buffer Overflow CAPEC-15: Command Delimiters Command Delimiters CAPEC-24: Filter Failure through Buffer Overflow Filter Failure through Buffer Overflow CAPEC-41: Using Meta-characters in E-mail Headers to Inject Malicious Payloads Using Meta-characters in E-mail Headers to Inject Malicious Payloads CAPEC-43: Exploiting Multiple Input Interpretation Layers Exploiting Multiple Input Interpretation Layers CAPEC-44: Overflow Binary Resource File Overflow Binary Resource File CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-46: Overflow Variables and Tags Overflow Variables and Tags CAPEC-47: Buffer Overflow via Parameter Expansion Buffer Overflow via Parameter Expansion CAPEC-52: Embedding NULL Bytes Embedding NULL Bytes CAPEC-53: Postfix, Null Terminate, and Backslash Postfix, Null Terminate, and Backslash CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic Using Slashes and URL Encoding Combined to Bypass Validation Logic CAPEC-67: String Format Overflow in syslog() String Format Overflow in syslog() CAPEC-71: Using Unicode Encoding to Bypass Validation Logic Using Unicode Encoding to Bypass Validation Logic CAPEC-73: User-Controlled Filename User-Controlled Filename CAPEC-78: Using Escaped Slashes in Alternate Encoding Using Escaped Slashes in Alternate Encoding CAPEC-79: Using Slashes in Alternate Encoding Using Slashes in Alternate Encoding CAPEC-80: Using UTF-8 Encoding to Bypass Validation Logic Using UTF-8 Encoding to Bypass Validation Logic CAPEC-88: OS Command Injection OS Command Injection CAPEC-92: Forced Integer Overflow Forced Integer Overflow CAPEC-120: Double Encoding Double Encoding CAPEC-182: Flash Injection Flash Injection CAPEC-267: Leverage Alternate Encoding Leverage Alternate Encoding

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-92087 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-92087 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by ce714d77-add3-4f53-aff5-83d477b104bb

    Sep. 16, 2026

    Action Type Old Value New Value
    Added Description @fastify/auth is a Fastify plugin that composes multiple authentication and authorization strategies into a single route guard. In versions 5.0.0 through 5.1.0, when strategies are composed with the relation "or" option together with the run "all" option and one entry is a nested array acting as an AND group, the group is evaluated in an order-dependent way: an earlier failing check is silently dropped and the group's result becomes the outcome of its last check. As a result, a request that satisfies only the last member of an AND group, for example an attacker who holds a valid API key but is not an administrator, is authorized instead of rejected, and a related order-dependent bypass affects the mirror configuration where the top-level relation is "and" and a nested group uses "or". The issue is fixed in @fastify/auth 5.1.1, and users should upgrade to 5.1.1 or later. As a workaround, omit the run "all" option where it is not required, order each AND group so its stricter check is evaluated last, or replace nested AND groups with an explicit top-level "and" composition.
    Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
    Added CWE CWE-285
    Added CWE CWE-697
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/92xxx/CVE-2026-92087.json">CVE-2026-92087</a>
    Added Reference https://cna.openjsf.org/security-advisories.html
    Added Reference https://github.com/fastify/fastify-auth/security/advisories/GHSA-7h52-2rwr-m76r
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 8.1
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact