CVE-2026-9138

MEDIUMCVSS 6.5/10EPSS 0.30%

Last modified

CVE-2026-9138 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. IBM Langflow OSS 1.0.0 through 1.11.2 Langflow could allow an authenticated attacker to write arbitrary files to the server due to improper input validation in the SaveToFileComponent. The application constructs local file paths using attacker‑controlled input without sufficient sanitization when handling requests to the /api/v1/run/{flow_id} endpoint. EPSS estimates a 0.30% chance of exploitation in the next 30 days.

Description

IBM Langflow OSS 1.0.0 through 1.11.2 Langflow could allow an authenticated attacker to write arbitrary files to the server due to improper input validation in the SaveToFileComponent. The application constructs local file paths using attacker‑controlled input without sufficient sanitization when handling requests to the /api/v1/run/{flow_id} endpoint. An attacker with low‑privileged authenticated access (such as a valid API key or user session) can supply crafted path values, including absolute paths or path traversal sequences, allowing arbitrary file writes to locations writable by the Langflow process. Successful exploitation may lead to unauthorized file creation or modification, potentially resulting in further compromise depending on the deployment environment.

Metrics

EPSS Probability
0.30%

22.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
LangflowLangflow>= 1.0.0, < 1.11.3

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-9138?
IBM Langflow OSS 1.0.0 through 1.11.2 Langflow could allow an authenticated attacker to write arbitrary files to the server due to improper input validation in the SaveToFileComponent. The application constructs local file paths using attacker‑controlled input without sufficient sanitization when handling requests to the /api/v1/run/{flow_id} endpoint. An attacker with low‑privileged authenticated access (such as a valid API key or user session) can supply crafted path values, including absolute paths or path traversal sequences, allowing arbitrary file writes to locations writable by the Langflow process. Successful exploitation may lead to unauthorized file creation or modification, potentially resulting in further compromise depending on the deployment environment.
How severe is CVE-2026-9138?
CVE-2026-9138 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.30% probability of exploitation in the next 30 days.
How do I fix CVE-2026-9138?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST