Vulnerability · Published Sep 27, 2026 · Assigned by VulnCheck

CVE-2026-101059utcp-http before 1.1.4 OAuth2 tokenUrl Trust Boundary Bypass

High 7.1

In plain English

A high-severity server-side request forgery in python-utcp from universal-tool-calling-protocol. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 13% of all known vulnerabilities).

Severity (CVSS 3.1)7.1High

Exploit odds (30 days)0.2%top 86.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

utcp-http before 1.1.4 fails to validate the OAuth2 tokenUrl field from remote OpenAPI specifications, allowing attackers to redirect credential submission to arbitrary endpoints. When a victim registers an attacker-controlled OpenAPI spec and invokes a generated OAuth2-protected tool, the library POSTs the victim's client_id and client_secret to the attacker-supplied token endpoint without URL validation.

Affected products (as reported)

Vendor	Product	Versions
universal-tool-calling-protocol	python-utcp	0 – before 1.1.4

Weakness: CWE-918 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N

References

GitHub Security Advisory (GHSA-8cp3-qxj6-px34) vendor-advisory
VulnCheck Advisory: utcp-http before 1.1.4 OAuth2 tokenUrl Trust Boundary Bypass third-party-advisory