CVE-2026-48508

Lemur has an authorization bypass in StrictRolePermission / AuthorityCreatorPermission

# lemur/auth/permissions.py
class AuthorityCreatorPermission(Permission):
    def __init__(self):
        requires_admin = current_app.config.get("ADMIN_ONLY_AUTHORITY_CREATION", False)
        if requires_admin:
            super().__init__(RoleNeed("admin"))
        else:
            super().__init__()              # empty Need set

class StrictRolePermission(Permission):
    def __init__(self):
        strict_role_enforcement = current_app.config.get("LEMUR_STRICT_ROLE_ENFORCEMENT", False)
        if strict_role_enforcement:
            needs = [RoleNeed("admin"), RoleNeed("operator")]
            super().__init__(*needs)
        else:
            super().__init__()              # empty Need set

def allows(self, identity):
    if self.needs and not self.needs.intersection(identity.provides):
        return False
    ...
    return True

A user holding only the read-only role can:

1. Create root Certificate Authorities. CA cert and private key are persisted in Lemur's DB with the attacker as owner. Any internal trust store that pins Lemur-managed roots can now be signed against by the attacker.
2. Upload arbitrary certificates via /certificates/upload, including attacker-supplied keys with destinations such as AWS push.
3. Create or modify notifications, which reach an SSRF sink (see related finding F3, Slack notification webhook).
4. Mark arbitrary domains as sensitive, manipulating Lemur's domain registry and the cert-issuance approval path.

Combined with any low-privilege credential leak (phished employee, leaked SSO token) or insider access, this is a pivot from "any authenticated identity" to control of the PKI issuance plane.

The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.

CVE-2026-48508 has a CVSS score of 8.8 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.9.1); upgrading removes the vulnerable code path.

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The config flag defaults for ADMIN_ONLY_AUTHORITY_CREATION and LEMUR_STRICT_ROLE_ENFORCEMENT were changed from False to True. Restrictive role enforcement is now active on all default installs without requiring explicit configuration.

class AuthorityCreatorPermission(Permission):
    def __init__(self):
        requires_admin = current_app.config.get("ADMIN_ONLY_AUTHORITY_CREATION", True)
        ...

class StrictRolePermission(Permission):
    def __init__(self):
        strict_role_enforcement = current_app.config.get("LEMUR_STRICT_ROLE_ENFORCEMENT", True)
        ...

Note: The opt-out branches (empty Needs) remain in the code. Operators who explicitly set ADMIN_ONLY_AUTHORITY_CREATION = False or LEMUR_STRICT_ROLE_ENFORCEMENT = False in their config will reintroduce the bypass. These flags should be left unset or set to True.

1. What is CVE-2026-48508? CVE-2026-48508 is a high-severity incorrect authorization vulnerability in lemur (pip), affecting versions <= 1.9.0. It is fixed in 1.9.1. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
2. How severe is CVE-2026-48508? CVE-2026-48508 has a CVSS score of 8.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of lemur are affected by CVE-2026-48508? lemur (pip) versions <= 1.9.0 is affected.
4. Is there a fix for CVE-2026-48508? Yes. CVE-2026-48508 is fixed in 1.9.1. Upgrade to this version or later.
5. Is CVE-2026-48508 exploitable, and should I be worried? Whether CVE-2026-48508 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-48508 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-48508? Upgrade lemur to 1.9.1 or later.

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