Vulnerability · Published Jun 23, 2026 · Assigned by GitHub_M

CVE-2026-55446Langflow: Unauthenticated DoS through multipart form boundary file upload

High 7.5

In plain English

A high-severity uncontrolled resource consumption in langflow from langflow-ai. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.6%top 52.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.0.19, an attacker can send a /api/v1/files/upload/ request without any authentication token/cookies and abuse a very long multipart form boundary to make the langflow app unusable for all users for an indefinite amount of time. This vulnerability is fixed in 1.0.19.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	langflow	1.0.19	GHSA-qwqc-p3q8-wcg9
PyPI	langflow	1.0.19	PYSEC-2026-223

Affected products (as reported)

Vendor	Product	Versions
langflow-ai	langflow	< 1.0.19

Weakness: CWE-400 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/langflow-ai/langflow/security/advisories/GHSA-qwqc-p3q8-wcg9 x_refsource_CONFIRM
https://github.com/langflow-ai/langflow/pull/3923 x_refsource_MISC