CVE-2026-22813 PUBLISHED

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

Assigner: GitHub_M
Reserved: 09.01.2026 Published: 12.01.2026 Updated: 13.01.2026

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.

Metrics

CVSS 4.0

CVSS Vector: 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
CVSS Score: 9.4

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	High
Attack Complexity	Low	Integrity	High	Integrity	High
Attack Requirements	None	Availability	High	Availability	High
Privileges Required	None
User Interaction	Passive

CVSS 4.0

Product Status

Vendor	anomalyco
Product	opencode
Versions	Version < 1.1.10 is affected

References

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

Problem Types

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