---
id: CVE-2026-71303
title: Lemur manages TLS certificate creation
summary: >-
  Lemur manages TLS certificate creation. Prior to 1.9.3, _validate_acme_url
  enforced ACME_DIRECTORY_HOST_ALLOWLIST when an authority was created, but PUT
  /api/1/authorities/ passed options to lemur/authorities/service.py without
  applying …
severity: high
cvss: 7.7
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N'
cwe:
  - CWE-918
vendor: lemur
product: lemur
affected:
  - lemur <= 1.9.2
patched:
  - lemur 1.9.3
published: '2026-08-18'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T21:02:26.047'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-71303'
references:
  - url: >-
      https://github.com/Netflix/lemur/commit/edca0390f930344d65ff4ca37a669c2320e3dfad
    label: security-advisories@github.com
  - url: 'https://github.com/Netflix/lemur/releases/tag/v1.9.3'
    label: security-advisories@github.com
  - url: 'https://github.com/Netflix/lemur/security/advisories/GHSA-v5rc-cpwc-cfpr'
    label: security-advisories@github.com
  - url: 'https://github.com/Netflix/lemur/security/advisories/GHSA-v5rc-cpwc-cfpr'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://github.com/advisories/GHSA-v5rc-cpwc-cfpr'
tags:
  - nvd
  - ghsa
  - pip
epss: 0.00268
epssPercentile: 0.19211
aliases:
  - GHSA-v5rc-cpwc-cfpr
ecosystem: pip
ingestedAt: '2026-08-18T21:22:59.760Z'
---

## Overview

Lemur manages TLS certificate creation. Prior to 1.9.3, _validate_acme_url enforced ACME_DIRECTORY_HOST_ALLOWLIST when an authority was created, but PUT /api/1/authorities/ passed options to lemur/authorities/service.py without applying the same check. A user holding an authority role could replace the stored acme_url with an internal service or instance-metadata URL such as 169.254.169.254. The next issuance operation loaded that value and passed it to ClientV2.get_directory, causing an outbound request from the Lemur backend. This bypassed the creation-time mitigation for CVE-2026-55166 and could expose internal services or cloud metadata. The fix revalidates acme_url whenever authority options are updated. This issue is fixed in version 1.9.3.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-71303)

Affected packages:

- `lemur <= 1.9.2`

Patched in:

- `lemur 1.9.3`

Source: https://github.com/advisories/GHSA-v5rc-cpwc-cfpr