CVE-2026-48508 Lemur: Authorization bypass in StrictRolePermission / AuthorityCreatorPermission
Read-only users can create root CAs and upload certificates due to a permission bypass when specific security flags are disabled.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-48508?
CVE-2026-48508 is a high-severity missing authorization vulnerability in Netflix lemur, published on 18 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Weakness: CWE-863
Which versions are affected by CVE-2026-48508?
3 open source packages ship an affected version, including lemur.
| Package | Affected | Fixed in |
|---|---|---|
lemur PyPI | All versions | 1.9.1 |
lemur PyPI | All versions | 1.9.1 |
lemur PyPI | All versions | 1.9.1 |
How do I fix CVE-2026-48508?
Upgrade lemur to 1.9.1 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-48508 being exploited?
There is no known exploitation of CVE-2026-48508 in the wild and no public exploit code.
Sources
Also known as GHSA-qcqw-jwxc-2hqg, PYSEC-2026-2588.