langflow-ai langflow up to 1.8.3 Model Context Protocol Configuration API mcp_projects.py get_client_ip/install_mcp_config X-Forwarded-For injection

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.6$0-$5k3.42

Summaryinfo

A vulnerability, which was classified as critical, was found in langflow-ai langflow up to 1.8.3. This affects the function get_client_ip/install_mcp_config of the file src/backend/base/langflow/api/v1/mcp_projects.py of the component Model Context Protocol Configuration API. Executing a manipulation of the argument X-Forwarded-For can lead to injection. The identification of this vulnerability is CVE-2026-6599. The attack may be launched remotely. Furthermore, there is an exploit available. The application of restrictive firewalling is recommended. The vendor was contacted early about this disclosure but did not respond in any way.

Detailsinfo

A vulnerability was found in langflow-ai langflow up to 1.8.3. It has been declared as critical. This vulnerability affects the function get_client_ip/install_mcp_config of the file src/backend/base/langflow/api/v1/mcp_projects.py of the component Model Context Protocol Configuration API. The manipulation of the argument X-Forwarded-For with an unknown input leads to a injection vulnerability. The CWE definition for the vulnerability is CWE-74. The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. As an impact it is known to affect confidentiality, integrity, and availability.

The advisory is available at gist.github.com. This vulnerability was named CVE-2026-6599. The exploitation appears to be easy. The attack can be initiated remotely. Technical details and also a public exploit are known. This vulnerability is assigned to T1055 by the MITRE ATT&CK project.

It is possible to download the exploit at gist.github.com. It is declared as proof-of-concept. The vendor was contacted early about this disclosure but did not respond in any way.

Proper firewalling of is able to address this issue.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.3
VulDB Meta Temp Score: 5.6

VulDB Base Score: 6.3
VulDB Temp Score: 5.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Injection
CWE: CWE-74 / CWE-707 / CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Access: Public
Status: Proof-of-Concept
Download: 🔒
Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Firewall
Status: 🔍

0-Day Time: 🔒

Timelineinfo

04/19/2026 Advisory disclosed
04/19/2026 +0 days VulDB entry created
04/19/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: gist.github.com
Status: Not defined

CVE: CVE-2026-6599 (🔒)
GCVE (CVE): GCVE-0-2026-6599
GCVE (VulDB): GCVE-100-358234
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 04/19/2026 15:52
Changes: 04/19/2026 15:52 (60)
Complete: 🔍
Submitter: Eric-f
Cache ID: 216::103

Submitinfo

Accepted

  • Submit #791922: Langflow <= 1.8.3 Authentication Bypass by Spoofing (by Eric-f)

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Interested in the pricing of exploits?

See the underground prices here!