CISA Flags Actively Exploited Langflow Flaws as Attackers Pursue RCE and Cross-Tenant Access

CISA added Langflow vulnerabilities to its Known Exploited Vulnerabilities catalog after evidence of active attacks, ordering U.S. federal agencies to remediate CVE-2026-55255 by July 10. The flaw is an insecure direct object reference in /api/v1/responses that lets an authenticated attacker use a victim flow UUID to access another user's flow, exposing sensitive data and consuming the victim's resources. Reporting also tied Langflow to broader KEV updates, including CVE-2025-3248, a missing-authentication flaw in /api/v1/validate/code that allows unauthenticated remote code execution and was updated in CISA's catalog to show known ransomware use.

Sysdig said it observed in-the-wild exploitation of CVE-2026-55255 on June 25, alongside repeated abuse of CVE-2026-33017, an unauthenticated Langflow RCE that attackers appeared to prefer because it is easier to operationalize and provides direct host compromise. The observed operator enumerated flows through /api/v1/flows/, then abused POST /api/v1/responses with prompts such as "leak api keys" to trigger another tenant's flow and attempt credential theft, while also deploying a malicious Langflow component that fetched a second-stage shell script from 45.207.216.55:8084. Researchers assessed the activity as automated, opportunistic, and financially motivated, combining credential theft, compute abuse, implant delivery, and botnet-style monetization.