CVE-2026-58201 Lokka: Azure Resource Manager URL path validation issue
An attacker can manipulate URL paths to leak Azure Resource Manager bearer tokens to unintended hosts in the Lokka MCP server.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-58201?
CVE-2026-58201 is a high-severity server-side request forgery vulnerability in merill lokka, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Lokka is a Model Context Protocol server for Microsoft 365, including Microsoft Graph and other services. Prior to 2.1.2, the Lokka-Microsoft tool in src/mcp/src/main.ts uses direct URL string concatenation to append the user-controlled path value to the management.azure.com base URL. A specially crafted path can alter URL authority parsing and cause an Azure Resource Manager bearer token to be sent to an unintended host. This issue is fixed in version 2.1.2.
Weakness: CWE-918
Which versions are affected by CVE-2026-58201?
2 open source packages ship an affected version, including @merill/lokka.
| Package | Affected | Fixed in |
|---|---|---|
@merill/lokka npm | All versions | 2.1.2 |
@merill/lokka npm | All versions | 2.1.2 |
How do I fix CVE-2026-58201?
Upgrade @merill/lokka to 2.1.2 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-58201 being exploited?
There is no known exploitation of CVE-2026-58201 in the wild and no public exploit code.
Sources
Also known as GHSA-g2gw-q38m-vjfc.