8.7

CVE-2026-0621: anthropic mcp typescript sdk

CVSS: 8.7v4.0HighAnalyzed
AliasesCGA-7gpv-4r5m-68hvCGA-7rpx-4gh3-fqfqCGA-x59c-g5vr-9h34
Published 05-01-2026Last modified 08-10-2026
Open JSON

Vulnerability summary

CVE-2026-0621 is a high (CVSS 8.7) vulnerability in anthropic mcp typescript sdk. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 37% of scored vulnerabilities. 1 public exploit is recorded.

Overall risk
45/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.7/10
010
High · v4.0 (CVE.org)
EPSS score
0.44%
0%100%
Low · -0.01 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1github

Advisory lineage

Upstream 0 · Downstream 0 · Related 1
CGA-8VM3-WFQP-6GC6

Timeline

  1. 05-01-2026
    PublishedVulnerability first disclosed.
  2. 08-10-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

6 scores · 5 sources · 2 versions

EPSS trend

Probability

0.44%

Chance of exploitation in the next 30 days

Percentile

37%

Versus all other CVEs

30-day change

-0.01 pp

From 0.45% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.44%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

1 found
  • githubUnverified

    Typescript Sdk

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Chainguard12 products
  • gemini-cli< 0.49.0-r4
  • kibana-9.1< 9.1.9-r2
  • kibana-9.1-iamguarded< 9.1.9-r2
  • kibana-9.2< 9.2.3-r2
  • kibana-9.2-iamguarded< 9.2.3-r2
Wolfi2 products
  • langfuse-3< 3.145.0-r0
  • langfuse-3-worker< 3.145.0-r0
@modelcontextprotocol1 product
  • sdk≥ 1.3.0, < 1.25.2
Anthropic1 product
Lfprojects1 product

5 vendors · 17 products

References

9 links