CVE-2026-58497 Uni-CLI: Legacy HTTP MCP transport accepted browser-originated localhost requests
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-58497?
CVE-2026-58497 is a high-severity vulnerability in olo-dot-io Uni-CLI, published on 23 Oct 2026.
Official description
Uni-CLI gives people and agents one command interface for websites, browsers, desktop applications, local tools, and MCP. Prior to version 0.225.2, Uni-CLI exposed the legacy JSON-RPC-over-HTTP MCP transport on loopback without validating browser Origin headers before routing requests. A malicious web page could send a CORS simple POST request, such as text/plain, to the local /mcp endpoint and deliver a JSON-RPC body to the dispatcher. If the user had started the local MCP HTTP transport, that page could drive tools/call requests against the user's local Uni-CLI server. The Streamable HTTP transport already enforced this browser-to-localhost boundary. The legacy stateless HTTP path did not, so the two HTTP transports had drifted. This issue is about the browser-to-localhost boundary; it does not change Uni-CLI's local-code-execution trust model. This issue has been patched in version 0.225.2.
Which versions are affected by CVE-2026-58497?
2 open source packages ship an affected version, including @zenalexa/unicli.
| Package | Affected | Fixed in |
|---|---|---|
@zenalexa/unicli npm | All versions | 0.225.2 |
@zenalexa/unicli npm | All versions | 0.225.2 |
How do I fix CVE-2026-58497?
Upgrade @zenalexa/unicli to 0.225.2 or later.
Is CVE-2026-58497 being exploited?
There is no known exploitation of CVE-2026-58497 in the wild and no public exploit code.
Sources
Also known as GHSA-v3f4-w7r7-v3hm.