---
title: "CVE-2026-22813: Malicious website can execute commands on the local system through XSS in the OpenCode web UI"
url: https://erroneo.us/security/cve/CVE-2026-22813/
description: "CVE-2026-22813 (opencode-ai (npm)): OpenCode is an open source AI coding agent. The markdown renderer used for LLM responses will insert arbitrary HTML into…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-01-12
date_modified: 2026-01-13
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-22813"
kev: false
cvss: 9.4
epss: 0.00905
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-22813: Malicious website can execute commands on the local system through XSS in the OpenCode web UI

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.9% , percentile 59: FIRST’s model estimates a 0.9% chance of exploitation activity in the next 30 days, higher than 59% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Only applies if your dependency tree includes opencode-ai (npm) < 1.1.10, fixed in 1.1.10 . Check your lockfile, including transitive dependencies.

## What it is

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.

## Affected packages

- npm `opencode-ai` < 1.1.10 → fixed: 1.1.10

## Affected products (CVE record)

- anomalyco opencode: < 1.1.10

## Severity

- GitHub_M CVSS 4.0: 9.4 `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 CVSS 4.0: 9.4 `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`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.91% probability of exploitation activity in the next 30 days; percentile 59.

## Sources

- [GitHub Advisory GHSA-c83v-7274-4vgp](https://github.com/advisories/GHSA-c83v-7274-4vgp)
- [CVE.org record CVE-2026-22813](https://www.cve.org/CVERecord?id=CVE-2026-22813)
- [NVD entry CVE-2026-22813](https://nvd.nist.gov/vuln/detail/CVE-2026-22813)
- [github.com](https://github.com/anomalyco/opencode/security/advisories/GHSA-c83v-7274-4vgp)

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Source page: https://erroneo.us/security/cve/CVE-2026-22813/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt