CVE-2026-45366Network attack vector

Internal-service access via unvalidated OpenAPI server URL

Published May 28, 2026 · Updated May 28, 2026

SSRF in TypeScript UTCP @utcp/http before 1.1.2 allows remote attackers to read internal-service responses via a malicious OpenAPI spec. OpenApiConverter trusts servers[0].url, and callTool() sends an Axios request to that URL without reapplying the discovery allowlist. Exploitation requires the agent to register an attacker-controlled HTTPS spec and can expose cloud metadata, loopback services, or internal network responses.

CVSS severity4.7
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in TypeScript UTCP @utcp/http before 1.1.2 allows remote attackers to read internal-service responses via a malicious OpenAPI spec. OpenApiConverter trusts servers[0].url, and callTool() sends an Axios request to that URL without reapplying the discovery allowlist. Exploitation requires the agent to register an attacker-controlled HTTPS spec and can expose cloud metadata, loopback services, or internal network responses.

The record

CVE
CVE-2026-45366
Published
May 28, 2026
Updated
May 28, 2026
Vendor
Universal Tool Calling Protocol
Product
TypeScript UTCP
Classifications
CWE-918, T1090
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 28, 2026CVE publishedPublication date reported by the CVE source.
  2. May 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.1.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Universal Tool Calling Protocol · TypeScript UTCPversion=< 1.1.2

Published CVSS scores

4.7GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1090Proxy

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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