Dashboard / CVE-2026-0621

CVE-2026-0621

HIGH
MEDIUM Priority: 0.04 BB Relevance: 77/100
Published: 2026-01-05 Modified: 2026-10-26 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Auth No Interaction

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: None
S: X
AT: None
VC: None
VI: None
VA: High

Description

Anthropic's MCP TypeScript SDK versions up to and including 1.25.1 contain a regular expression denial of service (ReDoS) vulnerability in the UriTemplate class when processing RFC 6570 exploded array patterns. The dynamically generated regular expression used during URI matching contains nested quantifiers that can trigger catastrophic backtracking on specially crafted inputs, resulting in excessive CPU consumption. An attacker can exploit this by supplying a malicious URI that causes the Node.js process to become unresponsive, leading to a denial of service.

Weakness Classification (1)

Affected Software (1)

VendorProductVersion
lfprojects mcp_typescript_sdk < 1.25.1

References & Advisories (2)

Bug Bounty Relevance

77 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity
✓ No user interaction

CVSS Score

8.7 / 10.0 v4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS — Exploitation Probability

0.44%
Raw Score 0.004380
Percentile 38.0%
Date 2026-10-29

EPSS Trend

2026-10-29
0.00438
2026-10-28
0.00438

Intelligence Sources

nvd ref →

External Links