CVE-2026-71317
MediumCVSS 6.5Exploitation Probability (EPSS)
Low risk0th percentile - higher than 0% of all known CVEs
Summary
Lemur prior to 1.9.3 did not require AuthorityPermission on the parent authority when creating a sub-CA if ADMIN_ONLY_AUTHORITY_CREATION was false. An authenticated non-read-only user could create a sub-CA and use the parent's private key to sign a new intermediate, allowing issuance of trusted certificates outside normal controls.
Risk Assessment
The risk includes unauthorized certificate issuance, potentially leading to compromise of PKI trust and enabling man-in-the-middle attacks.
Recommendation
Upgrade Lemur to version 1.9.3 or later and enable ADMIN_ONLY_AUTHORITY_CREATION if possible.
Original NVD description (English source)
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.