> CVE-2026-55166 [CRITICAL]

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PUBLISHED
2026-08-18 19:16
MODIFIED
2026-08-18 19:16
CVSS_SCORE V3
9.9
EPSS (Prob. Exploit)
0.29%
Top 80.2%
DATA SOURCES:
NVD 🔗 2026-08-18 CWE MITRE 🔗 2026-09-01 FIRST EPSS 🔗 2026-10-18 OSV 🔗 2026-10-26

> 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.

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L
EXPLOITABILITY
3.1
IMPACT
6.0

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
Low (L)
Peu de conditions requises pour exploiter
PR (Privilèges Requis)
Privileges Required
Low (L)
Authentifié avec compte utilisateur basique
UI (Interaction Utilisateur)
User Interaction
None (N)
Aucune interaction utilisateur nécessaire
S (Périmètre)
Scope
Changed (C)
Impact s'étend au-delà du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
High (H)
Divulgation totale d'informations
I (Impact Intégrité)
Integrity Impact
High (H)
Modification totale des données possible
A (Impact Disponibilité)
Availability Impact
Low (L)
Interruption partielle du service possible

> RÉSUMÉ DES IMPACTS

Confidentialité
High
Divulgation totale d'informations
Intégrité
High
Modification totale des données possible
Disponibilité
Low
Interruption partielle du service possible

> WEAKNESSES

CWE-285 CWE-639 CWE-918

> CWE DETAILED DESCRIPTIONS

CWE-285: Improper Authorization - The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. | CWE-639: Authorization Bypass Through User-Controlled Key - The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. | CWE-918: Server-Side Request Forgery (SSRF) - The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

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

AFFECTED PACKAGES:
Unknown / Unknown
33 versions affected
ALIASES:
GHSA-v2wp-frmc-5q3v, PYSEC-2026-384

> HISTORIQUE DES MODIFICATIONS

Première apparition
18/08/2026 19:16
Source: NVD
📊 ENRICHISSEMENT 01/09/2026 06:02
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-285: Improper Authorization - The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. | CWE-639: Authorization...
Total des modifications: 1 Dernière mise à jour: 1 month ago

> REFERENCES

https://github.com/Netflix/lemur/commit/872f6e282542352f2bf3f6e2bcc504ab81e1843d
https://github.com/Netflix/lemur/releases/tag/v1.9.2
https://github.com/Netflix/lemur/security/advisories/GHSA-v2wp-frmc-5q3v
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