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CVE-2026-55166— Lemur: any SSO-authenticated user achieves AWS IAM compromise and permanent PKI key access via ACME acme_url SSRF and creator-equality IDOR

Quick assessment

Affected
Netflix lemur
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Netflix lemur是美国Netflix公司开源的一个证书管理工具。 Netflix Lemur 1.9.2之前版本存在安全漏洞，该漏洞源于对ACME authority的acme_url参数缺少有效的服务端目标限制，导致服务端请求伪造，同时证书导出权限验证不足，可能导致经过身份验证的攻击者获取云实例凭据或访问长期PKI私钥。

CVSS 9.9 · Critical EPSS 0.22% · P12

Affected Version Matrix 1

VendorProduct Version RangeStatus
Netflix lemur < 1.9.2 affected
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I. Basic Information for CVE-2026-55166

Vulnerability Information
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Vulnerability Title
Lemur: any SSO-authenticated user achieves AWS IAM compromise and permanent PKI key access via ACME acme_url SSRF and creator-equality IDOR
Source: CVE Program / CVE List V5
Vulnerability Description
Lemur manages TLS certificate creation. Prior to 1.9.2, authenticated users could influence an ACME authority acme_url without an effective server-side destination restriction and trigger AcmeHandler.setup_acme_client to make backend requests. An attacker could target cloud instance metadata or internal services from Lemur network context, potentially obtaining credentials available to the host. The advisory also identifies creator-equality authorization behavior that could preserve access to certificate key material after ownership or role changes, with insufficient export_private_key audit context to distinguish that access path. Together, the acme_url server-side request forgery and authorization weakness could expose cloud credentials and long-lived PKI private-key access. The fix adds ACME_DIRECTORY_HOST_ALLOWLIST validation and enriches key-export audit events with creator and current-owner context. This issue is fixed in version 1.9.2.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
授权机制不恰当
Source: CVE Program / CVE List V5
Vulnerability Title
Netflix Lemur 授权问题漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Netflix lemur是美国Netflix公司开源的一个证书管理工具。 Netflix Lemur 1.9.2之前版本存在安全漏洞，该漏洞源于对ACME authority的acme_url参数缺少有效的服务端目标限制，导致服务端请求伪造，同时证书导出权限验证不足，可能导致经过身份验证的攻击者获取云实例凭据或访问长期PKI私钥。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Netflix lemur < 1.9.2 -

II. Public POCs for CVE-2026-55166

# POC Description Source Link Shenlong Link
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Qwen3.6-35B-A3B · 11118 chars
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III. Intelligence Information for CVE-2026-55166

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Patches & Fixes for CVE-2026-55166 (1)

Vendor Advisories for CVE-2026-55166 (1)

Vendor Pages for CVE-2026-55166 (1)

Same Patch Batch · Netflix · 2026-08-18 · 14 CVEs total

CVE-2026-48508 8.8 HIGH Lemur: Authorization bypass in StrictRolePermission / AuthorityCreatorPermission
CVE-2026-71308 8.1 HIGH Lemur: Unchecked `replaces[]` lets any user silence notifications and hijack auto-rotation
CVE-2026-71307 7.7 HIGH Lemur: Authenticated low-privilege users can read plaintext destination credentials (SFTP
CVE-2026-71303 7.7 HIGH Lemur: Incomplete fix for CVE-2026-55166 -- ACME authority update endpoint allows non-admi
CVE-2026-70666 7.4 HIGH Lemur: Server-Side Request Forgery via the ACME client following server-controlled URLs
CVE-2026-71417 7.3 HIGH Lemur: Any user can revoke arbitrary certificates at the CA by uploading a duplicate recor
CVE-2026-71317 6.5 MEDIUM Lemur: Sub-CA creation never checks `AuthorityPermission` on the parent authority
CVE-2026-70667 6.3 MEDIUM Lemur: SSRF protection in certificate revocation checking bypassable via HTTP redirects an
CVE-2026-55162 6.3 MEDIUM Lemur: Post-authentication SSRF via certificate verification - attacker-controlled CRL and
CVE-2026-55163 6.3 MEDIUM Lemur: Privilege escalation via PUT /api/1/roles/<id> — non-admin role members can rewrite
CVE-2026-55164 4.9 MEDIUM Lemur: Plaintext password storage in Lemur user-update path
CVE-2026-55165 4.8 MEDIUM Lemur : JWT verifier trusts attacker-supplied alg from token header — defense-in-depth gap
CVE-2026-71322 4.3 MEDIUM Lemur: Missing authorization check on POST /certificates/<id>/export for plugins with requ

IV. Related Vulnerabilities

Same product: lemur
Same vendor: Netflix
Same weakness: CWE-285

V. Comments for CVE-2026-55166

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