CyberRota Analysis
AI-GeneratedLemur versions prior to 1.9.3 are vulnerable to a flaw that allows users with authority roles to manipulate the `acme_url` parameter, potentially redirecting outbound requests to internal services or cloud metadata endpoints. This could lead to unauthorized access to sensitive internal data, effectively bypassing previous security mitigations. Organizations using Lemur for TLS certificate management should prioritize upgrading to version 1.9.3 to mitigate this high-severity risk.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
Note: these links are listed for security research and verification purposes only.
Original NVD Description
Lemur manages TLS certificate creation. Prior to 1.9.3, _validate_acme_url enforced ACME_DIRECTORY_HOST_ALLOWLIST when an authority was created, but PUT /api/1/authorities/ passed options to lemur/authorities/service.py without applying the same check. A user holding an authority role could replace the stored acme_url with an internal service or instance-metadata URL such as 169.254.169.254. The next issuance operation loaded that value and passed it to ClientV2.get_directory, causing an outbound request from the Lemur backend. This bypassed the creation-time mitigation for CVE-2026-55166 and could expose internal services or cloud metadata. The fix revalidates acme_url whenever authority options are updated. This issue is fixed in version 1.9.3.