How severe is CVE-2026-8859?

CVE-2026-8859 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-8859 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-8859?

CVE-2026-8859 affects Langflow. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-8859?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-8859 published?

CVE-2026-8859 was published on 2026-07-17 and last updated on 2026-07-23.

CVE-2026-8859

CVE-2026-8859 is a critical-severity vulnerability in Langflow with a CVSS 3.x base score of 9.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Severity: Critical (CVSS 3.x base score 9.9)
EPSS exploit prediction: 0% (30th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-22
Affected product: Langflow
Published: 2026-07-17
Last modified: 2026-07-23

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.

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.
How severe is CVE-2026-8859?: CVE-2026-8859 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-8859 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-8859?: CVE-2026-8859 affects Langflow. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-8859?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-8859 published?: CVE-2026-8859 was published on 2026-07-17 and last updated on 2026-07-23.

References

https://www.ibm.com/support/pages/node/7278924

Affected products (1)

cpe:2.3:a:langflow:langflow:*:*:*:*:*:*:*:*

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