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Critical CVSS 9.6

CVE-2026-46409

NVD analysis in progress

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.

What this means

Exposure
Exploitable remotely over the network and without authentication — but only if a user opens booby-trapped content.
Impact
An attacker can read sensitive data, modify or destroy data and take the service offline. The impact spreads beyond the vulnerable component into other parts of the system.
Weakness
The application interprets attacker-supplied code, which then runs with its privileges.
Likelihood
Its EPSS score stays low: nothing points to imminent exploitation, which is no reason to leave it unpatched.

What to doPatch without waiting for the next scheduled cycle.

Read automatically from the CVSS vector, the weakness type (CWE) and the EPSS score. The technical description above remains the one published by NIST.

Published
7 August 2026
CVSS
9.6 (v3.1) 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 within 30 days · above 29% of all CVEs
Weakness
CWE-94CWE-306CWE-346
Sources
nvd
References

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