DeepChat: Incomplete Fix for CVE-2025-55733 leads to Remote Code Execution via Markdown Links bypassing `isValidExternalUrl`_CVE-2026-43899

{
    "lastseen": "",
    "description": "DeepChat is an open-source artificial intelligence agent platform that unifies models, tools, and agents. Prior to v1.0.4-beta.1, An incomplete mitigation for CVE-2025-55733 leaves DeepChat vulnerable to an arbitrary protocol execution bypass (RCE). While the patch correctly restricted api.openExternal() inside the renderer's preload/index.ts script, it structurally neglected to sanitize native Electron pop-up window handlers. An attacker or a compromised AI endpoint returning a Markdown link can trigger a target=\"_blank\" native window interception in tabPresenter.ts, which forwards the malicious URL directly to shell.openExternal(url) and completely bypasses the isValidExternalUrl security boundary. This vulnerability is fixed in v1.0.4-beta.1.",
    "published": "2026-05-11T21:42:54.916Z",
    "modified": "2026-05-11T21:42:54.916Z",
    "type": "cve",
    "title": "DeepChat: Incomplete Fix for CVE-2025-55733 leads to Remote Code Execution via Markdown Links bypassing `isValidExternalUrl`",
    "source": "GitHub_M",
    "references": "https://github.com/ThinkInAIXYZ/deepchat/security/advisories/GHSA-cp8j-jx7q-7r5f",
    "id": "CVE-2026-43899",
    "bulletinFamily": "",
    "cwe": [
        "CWE-20"
    ],
    "cvelist": null,
    "sourceData": "ThinkInAIXYZ deepchat < 1.0.4-beta.1",
    "sourceHref": "",
    "cvss": {
        "score": 9.6,
        "severity": "CRITICAL",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "deepchat",
    "version": "< 1.0.4-beta.1",
    "vendor": "ThinkInAIXYZ",
    "ai_description": "Incomplete mitigation for CVE-2025-55733 allows arbitrary protocol execution bypass (RCE) via Markdown links",
    "ai_severity": "Critical",
    "ai_vendor": "ThinkInAIXYZ",
    "ai_product": "DeepChat",
    "ai_version": "< 1.0.4-beta.1",
    "ai_score": 9.6
}