CVE-2026-101059

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.

CVSS 4.0

7.1CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS 3.1

7.1CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N

EPSS

0.2% chance of exploitation in the next 30 days; higher than 12% of CVEs (scores of 2026-10-25)

CWE

CWE-918

Published

2026-09-27

Modified

2026-09-30

Record from

the NVD, synced 2026-10-19

References

• https://github.com/universal-tool-calling-protocol/python-utcp/security/advisories/GHSA-8cp3-qxj6-px34
• https://www.vulncheck.com/advisories/utcp-http-before-1.1.4-oauth2-tokenurl-trust-boundary-bypass
• https://github.com/universal-tool-calling-protocol/python-utcp/security/advisories/GHSA-8cp3-qxj6-px34

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