Attackers are actively exploiting CVE-2026-5027, a high-severity path traversal vulnerability in the open-source AI application platform Langflow, to write files to arbitrary locations on target systems and potentially achieve remote code execution. The flaw affects the POST /api/v2/files endpoint, where the filename parameter is not properly sanitized, and exploitation is made more severe by Langflow's default unauthenticated auto-login behavior, which lets attackers obtain a valid session token with a single unauthenticated request. VulnCheck reported observed attacks writing apparent test files to victim hosts, while Tenable identified the issue and assigned it a CVSS 8.8 score.
Internet exposure increases the risk: Censys data indicates about 7,000 Langflow instances are reachable online, with the largest concentration in North America. The exploitation report also fits a broader pattern of sustained attacker interest in Langflow, with other vulnerabilities including CVE-2026-0770, CVE-2026-21445, CVE-2026-33017, and CVE-2025-34291 also reported as exploited in 2026; the last has been linked in public reporting to the Iranian state-backed group MuddyWater. Separately, a newly disclosed flaw in Roxy-WI (CVE-2026-45556) shows a similar arbitrary file-write-to-RCE pattern on managed load balancers, but no public patch was available at publication.

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VulnCheck reported in-the-wild exploitation of CVE-2026-5027, a high-severity path traversal flaw in Langflow that can enable arbitrary file write and potential remote code execution. The observed activity involved attackers writing apparent test files to victim systems, aided by Langflow's default unauthenticated auto-login behavior.
A public disclosure described CVE-2026-45556 in Roxy-WI versions 8.2.6.4 and earlier as an authenticated path traversal and arbitrary file write issue in the WAF rule save functionality. The write primitive could be used to place files such as cron jobs on managed load balancers, leading to downstream remote code execution, and no public patch was available at publication.
Tenable publicly disclosed CVE-2026-5027 on March 27, 2026, describing a path traversal flaw in Langflow's file upload endpoint that could allow arbitrary file writes. The report said the issue had been reported earlier without response, and later fixes were released in langflow-base 0.8.3 and Langflow 1.9.0.
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