Dashboard / CVE-2026-123272

CVE-2026-123272

MEDIUM
MEDIUM Priority: 0.01 BB Relevance: 60/100
Published: 2026-11-05 Modified: 2026-11-08 First seen: 2026-11-05 Status: active

Attack Surface

Network Low Complexity No Auth

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: Active
AT: Present
VC: None
VI: None
VA: None

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.

Weakness Classification (1)

Affected Software (3)

VendorProductVersion
mark3labs mcp-go v0.48.0 < v1.2.1
mark3labs mcp-go v0.48.0 < v1.2.1
mark3labs mcp-go v0.48.0 < v1.2.1

References & Advisories (6)

Bug Bounty Relevance

60 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity

CVSS Score

5.1 / 10.0 v4.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N

EPSS — Exploitation Probability

0.20%
Raw Score 0.001960
Percentile 9.4%
Date 2026-11-14

EPSS Trend

2026-11-14
0.00196
2026-11-13
0.00196
2026-11-12
0.00196
2026-11-10
0.00196
2026-11-09
0.00196
2026-11-08
0.00196
2026-11-07
0.00196
2026-11-06
0.00196

Intelligence Sources

mitre ref →
nvd ref →

External Links