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Vulnerability · Published Aug 18, 2026 · Assigned by GitHub_M

CVE-2026-71417Lemur: Any user can revoke arbitrary certificates at the CA by uploading a duplicate record and revoking it

High 7.3

In plain English

A high-severity authorization bypass via user-controlled key in lemur from Netflix. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.3High
Exploit odds (30 days)0.1%top 98.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

Lemur manages TLS certificate creation. Prior to 1.9.3, POST /api/1/certificates/upload allowed a non-read-only user to create a duplicate row using another certificate body, authority_id, serial, or external_id without requiring permission on the underlying authority. PUT /api/1/certificates//revoke authorized the caller against only the selected Lemur row, so the creator of the duplicate bypassed CertificatePermission. The duplicate had no cert.endpoints, which also bypassed the safeguard that prevents revocation of deployed certificates. Issuer plugins then revoked the real CA-side certificate using certificate.body or external_id under the stored authority credentials. An attacker could therefore revoke arbitrary managed certificates and cause fleet-wide TLS denial of service. The fix rejects duplicate authority_id and serial identities, requires authority access on upload, and checks every matching row during revocation. This issue is fixed in version 1.9.3.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
PyPIlemur1.9.3GHSA-pxmc-2ffp-8j67
PyPIlemur1.9.3PYSEC-2026-3678

Affected products (as reported)

VendorProductVersions
Netflix lemur < 1.9.3

Weakness: CWE-639 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:H

References