CVE Vulnerabilities

CVE-2026-0621

Inefficient Regular Expression Complexity

Published: Jan 05, 2026 | Modified: Jan 30, 2026
CVSS 3.x
7.5
HIGH
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.x
RedHat/V2
RedHat/V3
Ubuntu
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Anthropics 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

The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.

Affected Software

NameVendorStart VersionEnd Version
Mcp_typescript_sdkLfprojects*1.25.1 (including)

Potential Mitigations

References