CVE-2026-9084

MISP OIDC authentication bypass via automatic email-based account linking under insecure IdP configurations

Published May 20, 2026 CVSS 4.0 · 6 Medium EPSS < 1% KEV · Not listed
Description
MISP’s OIDC authentication plugin allowed automatic linking of an OIDC identity to an existing local user account based on the email claim when the local account had no stored sub value. Under insecure or untrusted IdP configurations where email ownership is not enforced, an attacker with a valid OIDC token could assert a victim’s email address and authenticate as that user, leading to account takeover.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Misp
Misp misp
Vendors & Products Misp
Misp misp
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description MISP’s OIDC authentication plugin allowed automatic linking of an OIDC identity to an existing local user account based on the email claim when the local account had no stored sub value. Under insecure or untrusted IdP configurations where email ownership is not enforced, an attacker with a valid OIDC token could assert a victim’s email address and authenticate as that user, leading to account takeover.
Title MISP OIDC authentication bypass via automatic email-based account linking under insecure IdP configurations
Weaknesses CWE-287
References
Metrics cvssV4_0

{'score': 6, 'vector': 'CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
CIRCL
Published
Updated
May 20, 2026, 3:28 PM
Reserved
May 20, 2026, 2:21 PM
Status
Awaiting Analysis
Published
May 20, 2026, 4:16 PM
Modified
Jul 23, 2026, 12:10 PM