Vulnerability · Published Aug 18, 2026 · Assigned by GitHub_M
CVE-2026-71317Lemur: Sub-CA creation never checks `AuthorityPermission` on the parent authority
Medium 6.5
In plain English
A medium-severity missing authorization in lemur from Netflix. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | lemur | 1.9.3 | GHSA-g7p5-89mh-248h |
| PyPI | lemur | 1.9.3 | PYSEC-2026-3677 |
Affected products (as reported)
Weakness: CWE-862 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N
References
- https://github.com/Netflix/lemur/security/advisories/GHSA-g7p5-89mh-248h x_refsource_CONFIRM
- https://github.com/Netflix/lemur/commit/8669011203ca3dd89d9e39bab9ef6850eca723f9 x_refsource_MISC
- https://github.com/Netflix/lemur/releases/tag/v1.9.3 x_refsource_MISC