CVE-2026-4503

High

Published: 30 April 2026

Published

30 April 2026

Modified

11 May 2026

KEV Added

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Patch

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CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS Score 0.0003 8.4th percentile

Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-4503 is a high-severity Authorization Bypass Through User-Controlled Key (CWE-639) vulnerability in Langflow Langflow Desktop. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 8.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

This vulnerability is AI-related — categorised as LLM Application Platforms; in the Privacy and Disclosure risk domain.

The strongest mitigations our analysis identified are NIST 800-53 AC-3 (Access Enforcement) and AC-16 (Security and Privacy Attributes).

Deeper analysis

CVE-2026-4503 is an indirect object reference vulnerability (CWE-639) affecting IBM Langflow Desktop versions 1.0.0 through 1.8.4. The flaw arises from a user-controlled key that enables unauthorized access to other users' images, allowing an unauthenticated attacker to disclose sensitive image data without authentication.

A remote unauthenticated attacker can exploit this vulnerability over the network with low attack complexity, requiring no user privileges or interaction (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N, score 7.5 High). Successful exploitation grants high-impact confidentiality violations, permitting the attacker to view images belonging to other users.

IBM has published a security advisory with mitigation guidance at https://www.ibm.com/support/pages/node/7271099.

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2026-26435

Vulnerability details

IBM Langflow Desktop 1.0.0 through 1.8.4 Langflow could allow an unauthenticated user to view other users' images due to an indirect object reference through a user-controlled key.

CWE(s): CWE-639

AI Security AnalysisAI

AI Category: LLM Application Platforms
Risk Domain: Privacy and Disclosure
OWASP Top 10 for LLMs 2025: None mapped
Classification Reason: Matched keywords: langflow

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

Why these techniques?

The IDOR vulnerability in a network-accessible application (Langflow Desktop) directly enables remote unauthenticated exploitation for unauthorized data access, mapping to T1190 Exploit Public-Facing Application.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1