EUVD-2026-80788Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Attacker needs a valid low-privilege credential to reach the flawed AND-group evaluation (PR:L), remotely and reliably (AV:N/AC:L); escalated authorization exposes read/write (C:H/I:H) with no availability loss.
Primary rating from Vendor (openjs).
CVSS VectorVendor: openjs
Lifecycle Timeline
5DescriptionCVE.org
@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.
AnalysisAI
Authorization bypass in @fastify/auth versions 5.0.0 through 5.1.0 lets an authenticated low-privileged attacker who possesses a credential satisfying only the final member of a nested AND group, such as a valid API key without administrator rights, be authorized instead of rejected. The flaw occurs when strategies are composed with the relation "or" option together with the run "all" option and an entry is a nested array acting as an AND group, causing the group result to collapse to its last check; a mirror order-dependent bypass exists for top-level relation "and" with a nested "or" group. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Requires an application running @fastify/auth 5.0.0 through 5.1.0 that composes strategies using the relation 'or' option together with the run 'all' option where at least one entry is a nested array acting as an AND group (or the mirror configuration: top-level relation 'and' with a nested 'or' group). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N, base 8.1) is well-calibrated for an authorization-logic flaw: exploitation is network-reachable with low complexity, but PR:L is decisive - the attacker must already hold a valid low-privilege credential (e.g. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Vendor-released patch: upgrade @fastify/auth to 5.1.1 or later; this is the fixed version identified in the advisory. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, generate a dependency inventory (SBOM or npm audit across repositories and container images) to identify every application pinned to @fastify/auth 5.0.0, 5.0.x, 5.1.0, or any version below 5.1.1, and rank them by internet exposure; simultaneously have engineering flag any route definitions that compose strategies using the "or" relation option together with the "all" run option and a nested array, or the mirror case of a top-level "and" relation with a nested "or" group, since only those configurations trigger the bypass. …
Sign in for detailed remediation steps and compensating controls.
Threat intelligence, references, and detailed analysis are available after sign-in.
A vulnerability in the NuPoint Unified Messaging (NPM) component of Mitel MiCollab through 9.8 SP1 FP2 (9.8.1.201) could
FortiOS and FortiProxy contain an authentication bypass via the Node.js websocket module allowing unauthenticated remote
Denial of service against HTTP/2 server implementations allows remote unauthenticated attackers to exhaust server resour
Eval injection vulnerability in the internals.batch function in lib/batch.js in the bassmaster plugin before 1.5.2 for t
Flowise version 3.0.5 contains a remote code execution vulnerability in the CustomMCP node. The mcpServerConfig paramete
Node.js 8.5.0 before 8.6.0 allows remote attackers to access unintended files, because a change to ".." handling was inc
An issue was discovered in the node-serialize package 0.0.4 for Node.js. Rated critical severity (CVSS 9.8), this vulner
OpenSSL before 0.9.8za, 1.0.0 before 1.0.0m, and 1.0.1 before 1.0.1h does not properly restrict processing of ChangeCiph
Directory traversal vulnerability in the st module before 0.2.5 for Node.js allows remote attackers to read arbitrary fi
Multiple SQL injection vulnerabilities in the Manage Accounts page in the AccountManagement.asmx service in the Solarwin
The JS-YAML module before 2.0.5 for Node.js parses input without properly considering the unsafe !!js/function tag, whic
The AES-NI implementation in OpenSSL before 1.0.1t and 1.0.2 before 1.0.2h does not consider memory allocation during a
Same weakness CWE-285 – Improper Authorization
View allSame technique Authentication Bypass
View allShare
External POC / Exploit Code
Leaving vuln.today