TI-2026-49361 Aliases CVE-2026-70666 GHSA-xpmj-wjcp-6pww

Lemur: Server-Side Request Forgery via the ACME client following server-controlled URLs

LOW 32CWE-918Published 2026-08-18 · Updated 2026-08-19

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: Low
Impact type: —
Confidentiality · integrity · availability: Low · Low · Low
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.

Summary

Lemur manages TLS certificate creation. Prior to 1.9.3, an authority-role member could update acme_url through PUT /api/1/authorities/ without revalidation and direct setup_acme_client_no_retry to an attacker-controlled ACME server. ACME directory and order responses contain newNonce, newOrder, authorizations, and finalize URLs chosen by that server. The Lemur ClientV2 followed those URLs without requiring their host to match the configured directory host, allowing JWS-signed requests to internal services or cloud metadata endpoints. The issue required an ACME authority and a user authorized for that authority, but did not require global administrator privileges. The fix revalidates updates and introduces _PinnedClientNetwork to enforce a single allowed host for the complete ACME flow. This issue is fixed in version 1.9.3.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00216 12th percentileScored 2026-11-07

Fix Fixed lemur (Netflix): 1.9.3lemur (PyPI): 1.9.3

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Netflix	lemur	before 1.9.3	1.9.3	Patch available	CNA
—	lemur (PyPI)	before 1.9.3	1.9.3	Patch available	GHSA-xpmj-wjcp-6pww

lemur VendorNetflix Affected before 1.9.3 Fixed in 1.9.3 Patch available CNA
lemur (PyPI) Vendor— Affected before 1.9.3 Fixed in 1.9.3 Patch available GHSA-xpmj-wjcp-6pww

Remediation

Fix · CNA lemur (Netflix) Fixed in 1.9.3
Fix · GHSA-xpmj-wjcp-6pww lemur (PyPI) Fixed in 1.9.3 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-70666
2026-10-03 Alias added: GHSA-xpmj-wjcp-6pww

References

Other 4

TI-2024-04374 Path Traversal vulnerability via File Uploads in Genie CVSS 3.1CRITICAL 9.9
TI-2023-21044 Dispatch writes JWT tokens in error message CVSS 3.1CRITICAL 9.1
TI-2026-39854 Improper authorization in Netflix lemur CVSS 3.1CRITICAL 9.9
TI-2026-32272 Lemur: LDAP Filter Injection enables post-authentication privilege escalation CVSS 3.1HIGH 8.1
TI-2026-49966 Lemur: Unchecked `replaces[]` lets any user silence notifications and hijack auto-rotation for arbitrary certificates CVSS 3.1HIGH 8.1
TI-2026-49965 Missing authorization in Netflix lemur CVSS 3.1HIGH 7.7

See all 33 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences