CVE-2026-92288

9.1 CRITICAL

Published 2026-09-25 · Updated 2026-09-25

AI risk analysis

Summary: The flaw allows unauthenticated OAuth2 token introspection, enabling attackers to confirm token validity and extract metadata, potentially translating user identifiers across Relying Parties.
Exploitability: Exploitation is relatively easy for attackers who have an access token and know the client_id of a public Relying Party.
Blast radius: If exploited, the impact is significant as it can lead to the exposure of sensitive user information and the defeat of per-client and pseudonymous identifiers.
Detection: No reliable host or network indicator is derivable from the published description.
Prioritized remediation: Upgrade to Lemonldap::NG::Portal 2.21.6 or later.

auth-bypasswebmetadata-exposuretoken-introspection

Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.

NVD description

Lemonldap::NG::Portal versions from 2.20.0 before 2.21.6, from 2.22.0 before 2.23.4 for Perl allow unauthenticated OAuth2 token introspection because checkEndPointAuthenticationCredentials does not verify the client secret of a public Relying Party. checkEndPointAuthenticationCredentials() skips the secret comparison for a Relying Party marked public and still returns the authentication method deduced from the request, client_secret_basic or client_secret_post. introspection() rejects a caller only when that method is missing or none, so a request carrying a public client_id and an arbitrary or empty secret passes the endpoint's authentication check. An attacker who holds an access token and knows the client_id of any public Relying Party can confirm the token is active and read its metadata, including scope, audience, expiry and the sub claim. The sub claim is computed with the calling Relying Party's user identifier attribute, so an attacker can translate a user identifier from one Relying Party to another, defeating per-client and pseudonymous identifiers.

CVSS vector

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

Weaknesses

CWE-1390

All references

Source data: NVD (nvd.nist.gov), public domain. Exploit-DB.ai adds local AI analysis for defensive use only.

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