CyberRota Analysis
AI-GeneratedLemur's TLS certificate management system prior to version 1.9.3 is vulnerable due to improper handling of CRL and OCSP URL validation, allowing attackers to exploit HTTP redirects to access internal resources or perform DNS rebinding attacks. This could lead to unauthorized access to sensitive internal services when a certificate is uploaded through the API. Organizations using Lemur for certificate management should prioritize upgrading to version 1.9.3 to mitigate this risk.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
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Original NVD Description
Lemur manages TLS certificate creation. Prior to 1.9.3, _validate_revocation_url in lemur/certificates/verify.py checked the original CRL or OCSP URL but the later request could reach a different destination. The CRL requests.get call followed HTTP redirects without validating each Location target, so a public attacker-controlled URL could redirect to loopback, RFC1918, link-local, or instance-metadata addresses. Validation and connection also performed separate DNS resolutions, creating a time-of-check time-of-use window for DNS rebinding on both CRL and OCSP paths. An operator uploading a certificate through POST /api/1/certificates/upload could therefore induce blind internal requests despite the earlier mitigation. The fix disables redirects and pins validated addresses while preserving the correct Host value. This issue is fixed in version 1.9.3.