CVE-2026-92087
8.1 HIGHpublic exploit availablePublished 2026-09-16 · Updated 2026-09-17
AI risk analysis
- Summary
- The flaw allows an attacker to bypass authentication checks by manipulating the order of AND groups in the Fastify plugin configuration, potentially granting unauthorized access.
- Exploitability
- Exploitation is moderately hard as it requires precise manipulation of authentication strategy configurations, but preconditions include access to the API and knowledge of the specific authentication flow.
- Blast radius
- If exploited, the issue could grant unauthorized access to protected resources, leading to data breaches or other security incidents.
- Detection
- No reliable host or network indicator is derivable from the published description.
- Prioritized remediation
- Upgrade to @fastify/auth 5.1.1 or later.
Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.
NVD 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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Weaknesses
CWE-285, CWE-697
Public exploit & PoC references
References
Data: NVD (public domain). Analysis: local $0 model. Defensive use only.