CVE-2026-55446

Langflow: Unauthenticated DoS through multipart form boundary file upload

HIGH
7.5
CVSS Score
Published: June 23, 2026 at 04:26 PM UTC
Updated: October 25, 2026 at 11:10 PM UTC
2 products affected across 2 vendorsLangflowLangflow

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Severity
HIGH7.5
Exploit prediction
EPSS 0.6%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.0.19
Affected range stops below 1.0.19, so it looks safe — our inference, not a vendor statement
v < 1.0.19
Affected range stops below 1.0.19, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

x_refsource_CONFIRMExploitPatchVendor Advisory
Source: cverecord
https://github.com/langflow-ai/langflow/security/advisories/GHSA-qwqc-p3q8-wcg9
x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/langflow-ai/langflow/pull/3923

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-400

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