CVE-2026-123272

CVE-2026-123272CVE-2026-123272

Description

Mark3labs mcp-go before v1.2.1 contains an improper validation vulnerability in OAuthHandler.fetchServerMetadata that allows malicious MCP servers to obtain tokens for other resources by declaring arbitrary resources in well-known metadata. Attackers can declare a different MCP server as the RFC 8707 resource indicator, causing the authorization server to mint tokens the attacker replays against that resource.

Scoring

CVSS 8.0 ()
VectorCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
Last modified2026-11-05
Sourced from NVD. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.