CVE-2026-46409EPSS p29.0%
CVE-2026-46409CVE-2026-46409
Description
OpenYak is a local-first agent runtime for reliable tool-using models, with a desktop workspace built on top. Prior to version 1.1.3, the OpenYak desktop backend binds an HTTP API to `127.0.0.1:<random port>` (commonly 19141) without server-side Origin validation, loopback authentication, or Content-Type enforcement, and with a wildcard CORS policy. Any webpage a user visits while OpenYak is running can issue cross-origin requests to this local server — the browser acts as a proxy into loopback, bypassing OS-level network isolation. Chained, this lets a malicious page execute arbitrary shell commands on the host (RCE) via the build agent with `permission_presets.bash=true`, shut down the service, and exfiltrate chat history and account PII — with no user interaction beyond opening the page. Version 1.1.3 patches the issue.
Scoring
| CVSS | 9.6 () |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H |
| EPSS | 0.36% probability of exploitation · percentile 29.0% · 2026-08-08T12:02:54Z |
| Last modified | 2026-08-07 |