CVE-2026-8859

CRITICAL
Published Jul 17, 2026 Modified Jul 20, 2026 CWE-22

Description

IBM Langflow OSS 1.0.0 through 1.10.0 Langflow could allow an attacker to write arbitrary files to unintended locations due to improper input validation in the APIRequest component. A path traversal vulnerability exists when the "Save to File" feature is enabled, where filenames extracted from HTTP response Content-Disposition headers are not sanitized before being joined to the temporary directory path. An attacker controlling an external HTTP server can supply crafted filename values containing path traversal sequences (e.g., ../), enabling arbitrary file writes to locations accessible by the Langflow process.

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CVSS v3.1 Score

9.9
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0035
Probability of exploitation
0.28%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-22 Path Traversal

Affected Products

Vendor Product
langflow langflow
apple macos
linux linux_kernel
microsoft windows

References

Frequently Asked Questions

What is CVE-2026-8859? +
IBM Langflow OSS 1.0.0 through 1.10.0 Langflow could allow an attacker to write arbitrary files to unintended locations due to improper input validation in the APIRequest component. A path traversal vulnerability exists when the "Save to File" feature is enabled, where filenames extracted from HTTP response Content-Disposition headers are not sanitized before being joined to the temporary directory path. An attacker controlling an external HTTP server can supply crafted filename values containing path traversal sequences (e.g., ../), enabling arbitrary file writes to locations accessible by the Langflow process. It has a CVSS v3.1 base score of 9.9 (CRITICAL).
How severe is CVE-2026-8859? +
CVE-2026-8859 has a CVSS v3.1 score of 9.9 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0035, placing it in the 0th percentile for exploitation probability.
What products are affected by CVE-2026-8859? +
CVE-2026-8859 affects products from apple, langflow, linux, microsoft, specifically: langflow, linux_kernel, macos, windows. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2026-8859? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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