CVE-2026-101059 utcp-http before 1.1.4 OAuth2 tokenUrl Trust Boundary Bypass
Attackers can redirect OAuth2 credential submissions to malicious endpoints by providing unvalidated token URLs in OpenAPI specifications.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-101059?
CVE-2026-101059 is a high-severity server-side request forgery vulnerability in universal-tool-calling-protocol python-utcp, published on 27 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
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.
Weakness: CWE-918
Which versions are affected by CVE-2026-101059?
How do I fix CVE-2026-101059?
No fix has been published for CVE-2026-101059 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-101059 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-101059 exists.
Sources
Also known as GHSA-r549-qqpm-phj8.