Lemur: Post-authentication SSRF via certificate verification - attacker-controlled CRL and OCSP URLs in uploaded certificates
CVSS score
6.3
EPSS probability
%0.2
Risk score
0.0
Published
2 mo ago
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Vulnerability description
DayBreach CVE AI Research
CVE-2026-55162 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.
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.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-55162 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
| ID | VENDOR | PRODUCT | ACTION |
|---|---|---|---|
| 1 | netflix | lemur | View |
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 6.3 | CVSS V3_1 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L | CVE CNA |
| 6.3 | CVSS V31 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L | NVD |
Patch and Remediation Guide
Solution & Remediation Advisory
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Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-55162 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-55162 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
Similar Vulnerabilities
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