SEPTEMBER 18, 2026
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Case File

CVE-2026-55162

MEDIUM · CVSS 6.3 EPSS 0.20% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-08-18 · Last synced 2026-09-17

CyberRota Analysis

AI-Generated

Lemur versions prior to 1.9.2 are vulnerable to improper validation of CRL Distribution Point and OCSP responder URLs, allowing authenticated operators to exploit the system by submitting malicious certificates that can probe internal services and potentially cause side effects within the host network. Additionally, the unbounded cache for CRL paths can lead to memory exhaustion through attacker-controlled entries. Organizations using Lemur for TLS certificate management should prioritize upgrading to version 1.9.2 to mitigate these risks.

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.

CVE
CVE-2026-55162
Severity
MEDIUM
CVSS
6.3
EPSS
0.20%

Original NVD Description

Lemur manages TLS certificate creation. Prior to 1.9.2, lemur/certificates/verify.py accepted CRL Distribution Point and OCSP responder URLs from uploaded certificate extensions and used them in crl_verify and ocsp_verify without adequate destination validation. An authenticated operator could submit a certificate through POST /api/1/certificates/upload and cause verify_string to reach loopback, RFC1918, link-local, or instance-metadata destinations such as 169.254.169.254. The requests could probe internal services and create side effects from the Lemur host network position. The CRL path also used an unbounded cache, allowing attacker-controlled entries to persist and consume memory. The fix validates destinations, supports explicit trusted-host allowlists, and bounds the CRL cache. This issue is fixed in version 1.9.2.