CVE-2026-101058 python-utcp before 1.1.12 SSRF via Remote HTTP Manual
An attacker can trick a victim into registering a malicious UTCP manual, causing the client to send requests to local loopback services and return their data.
- 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-2026-101058?
CVE-2026-101058 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
python-utcp (pip package utcp-http) before 1.1.12 does not verify whether tool URLs declared in a hand-written UTCP manual point at the agent's own loopback interface when that manual is discovered from a remote, non-loopback origin. Because ensure_secure_url intentionally permits loopback HTTP for local development and native manuals bypassed the loopback check performed by the OpenAPI converter, an attacker who can serve a UTCP manual that a victim registers can cause the client to issue requests to services bound only to 127.0.0.1 on the victim host and have the response bodies returned to the caller (server-side request forgery). The http, sse and streamable_http protocols are all affected. Reach is limited to loopback, and exploitation further requires a loopback service that answers unauthenticated requests with useful data. Fixed in utcp-http 1.1.12, which rejects manuals fetched from a non-loopback origin that declare loopback tool URLs, keyed off the final post-redirect discovery URL.
Weakness: CWE-918
Which versions are affected by CVE-2026-101058?
How do I fix CVE-2026-101058?
No fix has been published for CVE-2026-101058 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-2026-101058 being exploited?
There is no known exploitation of CVE-2026-101058 in the wild and no public exploit code.
Sources
Also known as GHSA-88pp-fjxx-6p68.