CVE-2026-23733: Lobe Chat affected by Cross-Site Scripting(XSS) that can escalate to Remote Code Execution(RCE)

Should you act?

Normal patch cycle

No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.1%, percentile 4: FIRST’s model estimates a 0.1% chance of exploitation activity in the next 30 days, higher than 4% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs local access needed. Lower urgency for most teams unless an attacker could already run code on the machine.
• Only applies if your dependency tree includes @lobehub/chat (npm) <= 1.143.2, no fixed version listed. Check your lockfile, including transitive dependencies.

What it is

LobeChat is an open source chat application platform. Prior to version 2.0.0-next.180, a stored Cross-Site Scripting (XSS) vulnerability in the Mermaid artifact renderer allows attackers to execute arbitrary JavaScript within the application context. This XSS can be escalated to Remote Code Execution (RCE) by leveraging the exposed electronAPI IPC bridge, allowing attackers to run arbitrary system commands on the victim's machine. Version 2.0.0-next.180 patches the issue.

From the GitHub advisory

Summary A stored Cross-Site Scripting (XSS) vulnerability in the Mermaid artifact renderer allows attackers to execute arbitrary JavaScript within the application context. This XSS can be escalated to Remote Code Execution (RCE).

Details The vulnerability exists in the Renderer component responsible for rendering Mermaid diagrams within chat artifacts.

The content variable, which is derived from user or AI-generated messages, is passed directly to the component without any sanitization. The Mermaid library renders HTML labels (e.g., nodes defined with ["..."]) directly into the DOM. If the content contains malicious HTML tags (like ), they are executed.

PoC mermaid graph TD; A[" "];

Impact Remote Code Execution (RCE)

Weakness type: CWE-94.

Product: @lobehub/chat (npm) · Assigned by: GitHub_M · Published: 2026-01-18

Affected and fixed versions

Severity scores

• Attack vector: local access needed
• Attack complexity: high (needs special conditions)
• Privileges required: high (admin)
• User interaction: required (a user must click/open something)
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable no, technical impact partial.
• FIRST EPSS (model of 2026-10-21): 0.15% probability of exploitation activity in the next 30 days; percentile 4.

Timeline

• 2026-01-18 — CVE record published by GitHub_M
• 2026-01-20 — CVE record last updated
• 2026-01-20 — GitHub-reviewed advisory GHSA-4gpc-rhpj-9443 published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-4gpc-rhpj-9443 github.com
2. CVE.org record CVE-2026-23733 cve.org
3. NVD entry CVE-2026-23733 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com

Critical npm advisories · Today’s Security Digest