CVE-2026-9201 in Langflow OSS
Summary
by MITRE • 08/05/2026
IBM Langflow OSS 1.0.0 through 1.10.3 could allow an authenticated attacker to execute arbitrary code due to a cryptographic weakness in the custom component validation mechanism. When the optional hardening mode that restricts execution to trusted component templates is enabled, the application validates component code using a truncated SHA‑256 hash. Because the hash comparison relies on only a portion of the digest, an attacker can craft malicious component code that collides with a trusted template hash and bypasses validation. Successful exploitation allows the attacker to introduce and execute unauthorized Python code within the Langflow process, defeating the intended security control and potentially leading to full compromise of the affected instance.
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Analysis
by VulDB Data Team • 08/07/2026
This vulnerability exists in IBM Langflow Open Source Edition versions 1.0.0 through 1.10.3 where an authenticated attacker can exploit a cryptographic weakness in the custom component validation mechanism to execute arbitrary code. The flaw occurs when the hardening mode is enabled, which is designed to restrict execution to trusted component templates as a security control measure. The system implements a validation process that uses truncated SHA-256 hashes for comparing component code against trusted templates, creating a fundamental cryptographic weakness that undermines the intended security posture.
The technical implementation of this vulnerability stems from the use of truncated hash values in the validation process rather than full cryptographic digests. When the hardening mode is activated, Langflow performs component validation by comparing incoming component code against known good templates using only a portion of the SHA-256 hash output. This truncation creates a collision probability that allows an attacker to craft malicious component code that produces a hash value matching the truncated portion of a trusted template. The vulnerability specifically relates to CWE-327, which addresses use of a broken or weak cryptographic algorithm, and more specifically CWE-328 where the weakness lies in the truncation of cryptographic hashes.
The operational impact of this vulnerability is severe as it completely defeats the intended security control mechanism designed to prevent execution of untrusted code. An authenticated attacker with access to the system can bypass the validation checks and inject malicious Python code that executes within the Langflow process context. This arbitrary code execution capability allows for complete compromise of the affected instance, potentially enabling further lateral movement, data exfiltration, or persistence mechanisms. The vulnerability affects the core security model of the application by undermining the trust boundary established through component validation.
The mitigation strategy should focus on implementing proper cryptographic practices that use full hash values instead of truncated portions for validation comparisons. Organizations should immediately disable the hardening mode if it is enabled and ensure all systems are updated to versions that address this vulnerability through proper cryptographic implementation. Additionally, network segmentation and access controls should be implemented to limit the potential impact of any successful exploitation attempts. This vulnerability demonstrates the critical importance of following established security practices such as those outlined in NIST SP 800-57 for cryptographic key management and hash function usage, where truncated hashes should never be used for security validation purposes without proper consideration of collision probabilities.