{"id":"CVE-2026-43899","aliases":["EUVD-2026-29336","GHSA-cp8j-jx7q-7r5f"],"status":"published","title":"DeepChat: Incomplete Fix for CVE-2025-55733 leads to Remote Code Execution via Markdown Links bypassing `isValidExternalUrl`","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.","severity":{"version":"3.1","score":9.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-08","score":0.00401,"percentile":0.3465,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-20"],"published":"2026-05-11T21:42:54Z","modified":"2026-10-28T02:30:22Z","products":[{"vendor":"thinkinaixyz","product":"deepchat"}],"references":[{"url":"https://github.com/ThinkInAIXYZ/deepchat/security/advisories/GHSA-cp8j-jx7q-7r5f","tags":["x_refsource_CONFIRM","exploit","advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43899.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43899","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-43899","title":"DeepChat: Incomplete Fix for CVE-2025-55733 leads to Remote Code Execution via Markdown Links bypassing `isValidExternalUrl`","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.","status":"published","published":"2026-05-11T21:42:54.916Z","modified":"2026-05-12T12:52:30.296Z","cvss":[{"version":"3.1","score":9.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H","level":"critical","assessor":"cna"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T13:37:25.103021Z"}],"euvd":[{"id":"EUVD-2026-29336","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.","status":"published","published":"2026-05-11T21:42:54Z","modified":"2026-05-12T12:52:30Z","cvss":[{"version":"3.1","score":9.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T19:04:37.66514Z"}],"nvd":[{"id":"CVE-2026-43899","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.","status":"published","published":"2026-05-11T23:20:21.41Z","modified":"2026-10-26T18:10:00.173Z","cvss":[{"version":"3.1","score":9.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H","level":"critical","assessor":"secondary"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T14:12:18.239974Z"}],"osv":[{"id":"CVE-2026-43899","title":"DeepChat: Incomplete Fix for CVE-2025-55733 leads to Remote Code Execution via Markdown Links bypassing `isValidExternalUrl`","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.","status":"published","published":"2026-05-11T21:42:54.916Z","modified":"2026-10-28T02:30:22.179050379Z","cvss":[{"version":"3.1","score":9.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T15:45:04.820169Z"}]}}