CVE-2026-22813

Malicious website can execute commands on the local system through XSS in the OpenCode web UI

State: Published
Severity: 9.4 Critical
Published: Jan 12, 2026
Updated: Jan 13, 2026
Reserved: Jan 9, 2026

Description

OpenCode is an open source AI coding agent. The markdown renderer used for LLM responses will insert arbitrary HTML into the DOM. There is no sanitization with DOMPurify or even a CSP on the web interface to prevent JavaScript execution via HTML injection. This means controlling the LLM response for a chat session gets JavaScript execution on the http://localhost:4096 origin. This vulnerability is fixed in 1.1.10.

Scores

CVSS	Score	Vector	Source
4.0	9.4 Critical	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H	GitHub_M

Weaknesses

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Affected Products

Product	Versions
opencodeanomalyco	< 1.1.10Affected

References

https://github.com/anomalyco/opencode/security/advisories/GHSA-c83v-7274-4vgp

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