CVE-2026-71317 Lemur: Sub-CA creation never checks `AuthorityPermission` on the parent authority
Authenticated users can create unauthorized sub-CAs under internal roots when ADMIN_ONLY_AUTHORITY_CREATION is disabled, enabling trusted certificate issuance and potential key misuse.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-71317?
CVE-2026-71317 is a medium-severity missing authorization vulnerability in Netflix lemur, published on 18 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Lemur manages TLS certificate creation. Prior to 1.9.3, POST /api/1/authorities with type=subca did not require AuthorityPermission on the parent authority when ADMIN_ONLY_AUTHORITY_CREATION was false. AssociatedAuthoritySchema resolved the caller-supplied parent and passed it through authority creation to cryptography-issuer, which used the parent authority_certificate.private_key to sign a new intermediate. Any authenticated non-read-only user in that supported configuration could chain a sub-CA to an internal root for which the user held no role. The resulting intermediate could issue trusted certificates and its private key could be used outside Lemur, bypassing normal issuance controls. The fix checks AuthorityPermission on every supplied parent before invoking the issuer. This issue is fixed in version 1.9.3.
Weakness: CWE-862
Which versions are affected by CVE-2026-71317?
3 open source packages ship an affected version, including lemur.
| Package | Affected | Fixed in |
|---|---|---|
lemur PyPI | All versions | 1.9.3 |
lemur PyPI | All versions | 1.9.3 |
lemur PyPI | All versions | 1.9.3 |
How do I fix CVE-2026-71317?
Upgrade lemur to 1.9.3 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-71317 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-71317 exists.
Sources
Also known as GHSA-g7p5-89mh-248h, PYSEC-2026-3677.