Unpatched Langflow Flaw CVE-2026-5027 Exploited for Unauthenticated RCE

Summary

A critical path traversal vulnerability (CVE-2026-5027) in the open-source AI platform Langflow is being actively exploited. The flaw allows unauthenticated attackers to write files to arbitrary locations, leading to remote code execution due to Langflow's default unauthenticated auto-login. This exploitation follows a pattern of attacks targeting AI development tools, with thousands of Langflow instances exposed online.

Full text

Unpatched Langflow Flaw CVE-2026-5027 Exploited for Unauthenticated RCE Ravie LakshmananJun 10, 2026Vulnerability / Open Source A high-severity unpatched security flaw in Langflow, an open-source low-code platform to build artificial intelligence (AI) applications, has come under active exploitation in the wild, according to findings from VulnCheck. The vulnerability in question is CVE-2026-5027 (CVSS score: 8.8), a case of path traversal that could allow an attacker to write files to arbitrary locations. "The 'POST /api/v2/files' endpoint does not sanitize the 'filename' parameter from the multipart form data, allowing an attacker to write files to arbitrary locations on the filesystem using path traversal sequences ('../')," Tenable, which discovered the flaw, said in an alert released in late March 2026. The cybersecurity company said it attempted to contact the project maintainers three times in January and February 2026, before disclosing details of the issue on March 27. Caitlin Condon, vice president of security research at VulnCheck, said in a LinkedIn post that the vulnerability enables remote code execution. "Because Langflow enables unauthenticated auto-login by default, no credentials are required to reach the vulnerable endpoint, and a single unauthenticated request is sufficient to obtain a valid session token before proceeding with exploitation," Condon added. Exploitation efforts so far appear to weaponize the bug to write test files on victim systems. Data from Censys shows that there are about 7,000 Langflow instances publicly exposed on the internet, with a majority of them located in North America. The attack effort follows a flurry of exploitation activity targeting other Langflow vulnerabilities this year, including CVE-2026-0770, CVE-2026-33017, CVE-2026-21445, and CVE-2025-34291, the last of which has been weaponized by the Iranian state-sponsored group known as MuddyWater. "The activity underscores a growing trend of attackers targeting the infrastructure and tooling that organizations use to build and deploy AI applications," the company said in a statement shared with The Hacker News. Found this article interesting? Follow us on Google News, Twitter and LinkedIn to read more exclusive content we post. SHARE     Tweet Share Share Share SHARE  AI, Censys, cybersecurity, exploitation, Langflow, MuddyWater, Open Source, Path Traversal, remote code execution, Vulnerability ⚡ Top Stories This Week Chrome V8 Zero-Day CVE-2026-11645 Exploited in the Wild - Patch Now New FROST Attack Lets Websites Track What Sites and Apps You Open via SSD Timing One-Character Linux Kernel Flaw Enables Local Root Access, Exploits Now Public ⚡ Weekly Recap: Instagram Account Hacks, Android Zero-Day, GitHub Worm and More New ChatGPT Lockdown Mode Limits Tools That Could Enable Data Exfiltration Free Apps Are Quietly Turning Smart TVs Into Web-Scraping Proxies for AI AI Agent Uncovers 21 Zero-Days in FFmpeg; Chrome Patches Record 429 Bugs Miasma Worm Hits 73 Microsoft GitHub Repositories in Major Supply Chain Attack Cisco Patches CVE-2026-20230 in Unified CM as Exploit Code Goes Public Claude Code GitHub Action Flaw Let One Malicious Issue Hijack Repositories Microsoft Fixes One-Click GitHub Dev Attack That Let Attackers Steal OAuth Tokens Autonomous AI Tool Finds 2-Year-Old RCE Flaw in Redis (CVE-2026-23479) Microsoft 365 Android Apps Let Any App Steal Account Tokens via Leftover Debug Flag Unpatched Windows Search URI Vulnerability Lets Attackers Steal NTLMv2 Hashes New HTTP/2 Bomb Vulnerability Allows Remote DoS on NGINX, Apache, IIS, Envoy and Cloudflare ThreatsDay Bulletin: AI Agents Gone Wrong, Sketchy C2 Tools, ClickFix Tricks, JS Backdoors + 20 New Stories ⭐ Featured Resources Get the 2026 Guide to Govern and Secure Enterprise AI Agents at Scale Catch 88% of Malware Threats in Under 60 Seconds with Live Sandbox Analysis [Guide] Transform Network Operations with Intelligent Workflows See How Agentic AI Cuts Your SOC Triage Time in Half [Get a Demo]

Indicators of Compromise

• cve — CVE-2026-5027
• cve — CVE-2026-0770
• cve — CVE-2026-33017
• cve — CVE-2026-21445
• cve — CVE-2025-34291

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