Netflix Lemur up to 1.9.0 StrictRolePermission/AuthorityCreatorPermission permissions.py flask_principal.Permission.__init__ privileges management

Summaryinfo

A vulnerability was found in Netflix Lemur up to 1.9.0. It has been rated as critical. This impacts the function flask_principal.Permission.__init__ of the file lemur/auth/permissions.py of the component StrictRolePermission/AuthorityCreatorPermission. The manipulation leads to privileges management. This vulnerability is referenced as CVE-2026-48508. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in Netflix Lemur up to 1.9.0. It has been rated as critical. This issue affects the function flask_principal.Permission.__init__ of the file lemur/auth/permissions.py of the component StrictRolePermission/AuthorityCreatorPermission. The manipulation with an unknown input leads to a privileges management vulnerability. Using CWE to declare the problem leads to CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Lemur manages TLS certificate creation. Prior to 1.9.1, StrictRolePermission and AuthorityCreatorPermission in lemur/auth/permissions.py call flask_principal.Permission.__init__() with zero Need objects when ADMIN_ONLY_AUTHORITY_CREATION and LEMUR_STRICT_ROLE_ENFORCEMENT are unset because both flags default to False. Flask-Principal Permission.allows() returns True when self.needs is empty, so the .can() authorization gate permits every authenticated identity, including the read-only role. A read-only user can access POST /api/1/authorities, POST /api/1/certificates/upload, POST /api/1/pending_certificates//upload, POST /api/1/notifications, PUT or DELETE /api/1/notifications/, and POST /api/1/domains to create root Certificate Authorities, upload arbitrary certificates, create or edit notifications that reach an SSRF sink, and create domain entries. Explicitly setting either flag to False continues to opt into the permissive behavior. This issue is fixed in version 1.9.1.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-48508 since 05/21/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1068 according to MITRE ATT&CK.

Upgrading to version 1.9.1 eliminates this vulnerability.

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Productinfo

Vendor

• Netflix

Name

• Lemur

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9.0

Website

• Product: https://github.com/Netflix/lemur/

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