Cyber Posture

CVE-2026-43899

Critical

Published: 11 May 2026

Published
11 May 2026
Modified
12 May 2026
KEV Added
—
Patch
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CVSS Score 9.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
EPSS Score 0.0007 21.9th percentile
Risk Priority 19 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-43899 is a critical-severity Improper Input Validation (CWE-20) vulnerability. Its CVSS base score is 9.6 (Critical).

Operationally, ranked at the 21.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

This vulnerability is AI-related — categorised as Other AI Platforms.

Threat & Defense Details

Likely Mitigating ControlsAI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

PM-14 Testing, Training, and Monitoring
addresses: CWE-20

Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.

SA-11 Developer Testing and Evaluation
addresses: CWE-20

Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.

SI-10 Information Input Validation
addresses: CWE-20

Directly implements checks on information inputs to reject invalid data before processing.

SI-8 Spam Protection
addresses: CWE-20

Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.

NVD 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…

more

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.

Deeper analysisAI

Automated synthesis unavailable for this CVE.

Details

CWE(s)
CWE-20

AI Security AnalysisAI

AI Category
Other AI Platforms
Risk Domain
N/A
OWASP Top 10 for LLMs 2025
None mapped
Classification Reason
Matched keywords: artificial intelligence, ai

References