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Mallory
HighPublic exploit

Broken Access Control in Langflow Monitoring API

IdentifiersCVE-2026-21445CWE-306· Missing Authentication for…

CVE-2026-21445 is a critical broken access control vulnerability in Langflow, a platform for building and deploying AI-powered agents and workflows. In versions prior to the fix, multiple monitoring-related API endpoints lacked required authentication checks, allowing unauthenticated access to functionality that should have been restricted to authorized users. Reported affected routes include /api/v1/monitor/messages, /api/v1/monitor/transactions, and /api/v1/monitor/messages/session/{session_id}. As a result, remote attackers could query sensitive monitoring data such as user conversation content and transaction histories, and invoke destructive operations including message deletion. The issue is described as missing authentication controls on critical functions and aligns with CWE-306.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows unauthenticated remote attackers to access sensitive user conversation data and transaction histories, creating confidentiality and privacy exposure. It also permits destructive actions such as deleting messages by session, impacting integrity and availability of application data. In practice, this can result in data breach, privacy violations, operational disruption, and compliance risk where Langflow instances process personal or regulated data.

Mitigation

If you can’t patch tonight, do this now.

Until patching is completed, restrict network access to Langflow monitoring endpoints using firewall rules, IP allowlisting, reverse-proxy authentication, or VPN-only exposure. Disable or block access to the affected routes, including /api/v1/monitor/messages, /api/v1/monitor/transactions, and /api/v1/monitor/messages/session/{session_id}. Review exposed Langflow instances for unauthorized access to monitoring data and for destructive actions such as message deletion, and verify that authentication is enforced consistently across all API endpoints handling personal data or administrative operations.

Remediation

Patch, then assume compromise.

Upgrade Langflow to a fixed release. Supporting content indicates the production fix is Langflow 1.7.1 or later; some references also mention 1.7.0.dev45 as containing the patch. Where applicable, upgrade langflow-base to 0.7.1 or later. In addition to version updates, ensure the affected FastAPI routes in src/backend/base/langflow/api/v1/monitor.py enforce authentication, specifically by applying the authentication dependency such as dependencies=[Depends(get_current_active_user)] to the vulnerable monitoring endpoints.
PUBLIC EXPLOITS

Exploits

1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.

VALID 1 / 1 TOTALView more in app
CVE-2026-21445-PoCMaturityPoCVerified exploit

This repository provides a proof-of-concept (PoC) exploit for CVE-2026-21445, targeting the Langflow product (versions prior to 1.5.1) on Microsoft Windows. The main exploit script, 'CVE-2026-21445.py', is heavily obfuscated using PyArmor, making the actual exploit logic unreadable. The repository includes the PyArmor runtime and a license file to enable execution of the obfuscated code. Documentation files (README.md, docs/description.md, docs/mitigation.md) clarify that the PoC is for academic and defensive research only, and provide mitigation advice (upgrade Langflow, restrict network exposure, enable authentication and TLS). The README and mitigation docs indicate the exploit likely targets a network-exposed service and may involve malformed BSON requests. The repository structure is typical for a PoC: a main exploit script, obfuscation runtime, license, documentation, and screenshots. No hardcoded network endpoints or IPs are visible due to obfuscation, but the attack vector is network-based. The exploit is not weaponized and is intended for controlled research environments.

chinaxploiterDisclosed Jan 4, 2026pythonnetwork
EXPOSURE SURFACE

Affected products & vendors

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VendorProductType
LangflowLangflowapplication

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Threat actor evidence

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Associated malware

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Detection signatures1

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity11

Community discussion across Reddit, Mastodon, and other social sources.