CVE-2026-5027: Langflow RCE — Full Server Takeover Risk (June 2026)

CVE-2026-5027 — Langflow Remote Code Execution

CVE-2026-5027 is a high-severity remote code execution vulnerability in the open-source Langflow AI orchestration platform. The flaw allows unauthenticated attackers to perform path traversal and write arbitrary files, leading to full code execution on affected servers. Active exploitation is confirmed, with attacks attributed to the MuddyWater threat group. A patch has been available for over two months, but thousands of unpatched, internet-exposed Langflow instances remain at risk.

Attack Vector

Attackers exploit a path traversal weakness in Langflow's file handling routines, enabling them to write malicious files to arbitrary locations on the server. This allows execution of attacker-supplied code with the privileges of the Langflow process, resulting in full system compromise. No authentication is required, and exploitation is possible over the internet if the Langflow instance is exposed. Indicators of compromise include unexpected file creations, new or modified scripts in application directories, and outbound connections initiated by the Langflow process.

Who Is at Risk

All organizations running unpatched versions of Langflow, especially those with internet-facing deployments, are vulnerable. Thousands of instances are reportedly exposed globally. There are no reports of exploitation against non-Langflow systems, but any server running a vulnerable Langflow version is at risk of complete takeover.

Patch & Mitigate

• Patch: Upgrade immediately to the latest Langflow release containing the fix for CVE-2026-5027. Do not delay—attacks are ongoing.
• Workaround: Restrict network access to Langflow instances and disable unnecessary exposure until patching is complete.
• Detect: Monitor logs for unauthorized file writes, changes to application scripts, and unexpected outbound connections from Langflow servers.

MITRE ATT&CK

• TA0001 — Initial Access: Attackers exploit the vulnerability to gain a foothold on exposed servers.
• TA0005 — Defense Evasion: Malicious files may be disguised or hidden to evade detection post-compromise.
• TA0007 — Discovery: Once inside, attackers may enumerate system details to escalate privileges or move laterally.

Source: https://www.csoonline.com/article/4185063/langflow-rce-under-active-attack-months-after-a-patch-was-shipped.html