CVE-2026-0621 is a regular expression denial of service (ReDoS) vulnerability affecting Anthropic's MCP TypeScript SDK versions up to and including 1.25.1. Specifically, the UriTemplate class is susceptible to catastrophic backtracking when processing RFC 6570 exploded array patterns, leading to excessive CPU consumption. This vulnerability carries a high CVSS score of 8.7, indicating a network-based attack with low complexity that can result in a denial of service by rendering the Node.js process unresponsive. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
<= 1.25.1CPE matchmatch criteria | cpe:2.3:a:lfprojects:mcp_typescript_sdk:*:*:*:*:*:*:*:* |
CVSS version used by this source: 4.0
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
The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.
No media coverage found for this CVE.
The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.