{"id":"CVE-2026-43899","summary":"DeepChat: Incomplete Fix for CVE-2025-55733 leads to Remote Code Execution via Markdown Links bypassing `isValidExternalUrl`","details":"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.","aliases":["GHSA-cp8j-jx7q-7r5f"],"modified":"2026-07-15T01:48:58.984520351Z","published":"2026-05-11T21:42:54.916Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43899.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-20"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43899.json"},{"type":"ADVISORY","url":"https://github.com/ThinkInAIXYZ/deepchat/security/advisories/GHSA-cp8j-jx7q-7r5f"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43899"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/thinkinaixyz/deepchat","events":[{"introduced":"0"},{"fixed":"c4ce7be1d3061444362f8b6834a8c57119ae2847"}],"database_specific":{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"0"},{"fixed":"1.0.4-beta.1"}]}}],"versions":["v1.0.3","v1.0.3-beta.6","v1.0.3-beta.5","v1.0.3-beta.4","v1.0.3-beta.3","v1.0.3-beta.2","v1.0.3-beta.1","v1.0.2","v1.0.1","v1.0.0","v1.0.0-beta.7","v1.0.0-beta.6","v1.0.0-beta.5","v1.0.0-beta.4","v1.0.0-beta.3","v0.5.6-beta.1","v0.5.6-canary","v0.5.6","v0.5.5","v0.5.3","v0.5.2","v0.5.1","v0.5.0","v0.4.9","v0.4.8","v0.4.6","v0.4.5","workflow-19022687016","v0.4.3","v0.4.2","v0.4.1","v0.4.0","v0.3.9","v0.3.7","v0.3.6","v0.3.5","v0.3.4","v0.3.3","v0.3.2","v0.3.1","v0.3.0","v0.2.9","v0.2.8","v0.2.5","v0.2.4","v0.2.3-1","v0.2.3","v0.2.2","v0.2.1","v0.2.0-1","v0.2.0","v0.1.1","v0.1.0","v0.0.16","v0.0.15","v0.0.14","v0.0.13","v0.0.12","v0.0.10","v0.0.11","v0.0.9","v0.0.7","v0.0.6","v0.0.5","v0.0.3","v0.0.2","v0.0.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43899.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H"}]}