What is the CVSS score of CVE-2026-22813?

CVE-2026-22813 has a CVSS 3.1 base score of 6.1 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N. EPSS exploitation probability: 0.0%.

Is there a public PoC exploit available for CVE-2026-22813?

Yes, a public proof-of-concept exploit is available for CVE-2026-22813. Prioritise patching immediately. EPSS: 0.0%.

How to fix or mitigate CVE-2026-22813?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Verify Content-Security-Policy and output encoding.

Opencode CVE-2026-22813

MEDIUM

Cross-site Scripting (XSS) (CWE-79)

2026-01-12 security-advisories@github.com

GHSA-c83v-7274-4vgp

XSS AI / ML Opencode

6.1

CVSS 3.1 · GitHub Advisory

View

Vulnerability Assessment

Weakness	CWE CWE-79 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V1 - Encoding and Sanitization Output encoding, context-aware escaping MITRE ATT&CK 2 techniques across 2 tactics: Initial Access, Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS 6.1 (MEDIUM). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: Required. Exploitable via local access. Public exploit/POC available.
Exploit ScenarioDerived	An attacker could exploit this vulnerability to compromise the affected system.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

OpenCode's markdown renderer fails to sanitize HTML input in LLM responses, allowing attackers who control the chat output to inject arbitrary JavaScript that executes in the localhost:4096 origin without Content Security Policy protections. Public exploit code exists for this cross-site scripting vulnerability, affecting users of the AI coding agent through versions prior to 1.1.10. An attacker can achieve session compromise or local code execution by manipulating LLM responses to inject malicious scripts.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:54 CVSS 6.1

OpenCode is an open source AI coding agent. The markdown renderer used for LLM responses will insert arbitrary HTML into the DOM. [CVSS 6.1 MEDIUM]

RemediationAI

Fixed in version 1.1.10.. Implement output encoding and Content Security Policy headers. Restrict network access to the affected service where possible.

Affected Packages

npm opencode-ai fix: 1.1.10

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in npm

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Classified as CWE-79 (Cross-site Scripting (XSS)). Affects Opencode. 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.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

GitHub Advisory PRIMARY 6.1 MEDIUM

AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Lifecycle Timeline

Patch released

Mar 31, 2026 - 21:13 nvd

Patch available

PoC Detected

Jan 21, 2026 - 15:15 vuln.today

Public exploit code

CVE Published

Jan 12, 2026 - 23:15 nvd

MEDIUM 6.1

DescriptionGitHub Advisory

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.

Executive ViewAI

Why It Matters

Organizations using OpenCode should be aware of moderate risk from CVE-2026-22813, a cross-site scripting vulnerability rated CVSS 6.1. Attackers could inject scripts to steal sessions or perform actions as authenticated users. Proof-of-concept code is publicly available. Organizations should apply vendor updates when available and monitor for exploitation.

Business Impact: Low

Compensating Controls

Apply vendor patch. If patching is delayed: implement CSP headers, enable HttpOnly cookies, deploy WAF XSS rules.

Threat Intelligence Overview

EPSS Score

0.0%

Top 86% exploitable

Exploit

POC

Public exploit code exists

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS

GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity MEDIUM

CISA KEV No

Public POC Yes

EPSS 0.0%

Patch available Yes

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.