High severity · published Jun 23, 2026
CVE-2026-55446
Langflow: Unauthenticated DoS through multipart form boundary file upload
7.5
CVSS
0.6%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 48% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LA
langflow · langflow-ai
< 1.0.19 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-55446
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-55446
Issue Tracking
https://github.com/langflow-ai/langflow/pull/3923
Exploit
https://github.com/langflow-ai/langflow/security/advisories/GHSA-qwqc-p3q8-wcg9
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