CVE-2026-43899 in deepchat
Summary
by MITRE • 05/12/2026
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.
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Analysis
by VulDB Data Team • 06/29/2026
CVE-2025-55733 represents a critical arbitrary protocol execution vulnerability affecting DeepChat versions prior to v1.0.4-beta.1, demonstrating a fundamental flaw in the platform's security architecture that allows remote attackers to execute arbitrary commands on affected systems. This vulnerability specifically targets the Electron-based application framework where DeepChat operates, leveraging the inherent trust relationships between renderer processes and native system functions. The issue stems from an incomplete security mitigation that addressed one vector of attack while leaving another critical pathway open for exploitation.
The technical flaw manifests through a design oversight in the tabPresenter.ts module where native pop-up window handlers are not properly sanitized, creating a bypass mechanism for the intended security restrictions. Although the patch correctly restricted api.openExternal() calls within the renderer's preload/index.ts script, it failed to account for alternative code paths that could achieve the same outcome through different execution flows. The vulnerability exploits the target="_blank" attribute in Markdown links returned by compromised AI endpoints, which when processed by the tabPresenter.ts module, intercepts these pop-ups and directly forwards malicious URLs to shell.openExternal(url) without proper validation.
This security bypass allows an attacker to execute arbitrary protocols through the Electron application's native system integration points, effectively circumventing the isValidExternalUrl security boundary that was designed to prevent dangerous external URL access. The vulnerability operates at the intersection of web application security and native system integration, where the renderer process can potentially execute privileged system commands through the shell.openExternal() function call. This represents a classic example of insufficient input validation and improper sanitization of user-supplied content, which aligns with CWE-20 and CWE-74 categories that address improper neutralization of special elements used in OS command injection attacks.
The operational impact of this vulnerability is severe as it enables remote code execution on systems running affected DeepChat versions, potentially allowing attackers to gain full control over the affected machine. The attack vector through compromised AI endpoints demonstrates how modern AI platforms can become attack surfaces when they incorporate web-based content processing without proper security boundaries. An attacker could leverage this vulnerability to install malware, exfiltrate data, or establish persistent access to the target system. The vulnerability also aligns with ATT&CK technique T1059.007 which covers command and scripting interpreter for remote execution through legitimate system processes.
The mitigation implemented in version v1.0.4-beta.1 addresses the root cause by ensuring comprehensive sanitization of all native window handlers and eliminating bypass opportunities for the shell.openExternal() function. This fix demonstrates the importance of holistic security approaches that consider all potential code paths rather than addressing individual attack vectors in isolation. Security architects should recognize this as a case study in how seemingly minor architectural oversights can create significant security vulnerabilities, particularly in applications that integrate web technologies with native system capabilities. The vulnerability highlights the critical need for proper input validation and the principle of least privilege when dealing with system-level functions in Electron-based applications.
Organizations using DeepChat should immediately upgrade to version 1.0.4-beta.1 or later to address this vulnerability, as the bypass mechanism remains exploitable in older versions. The security patch demonstrates the importance of thorough regression testing when implementing security fixes and emphasizes that security measures must be comprehensive rather than partial. This vulnerability serves as a reminder that modern application security requires careful consideration of all potential attack surfaces, particularly in hybrid web-native applications where multiple security boundaries intersect.