The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has issued a fresh warning to federal agencies and private‑sector organizations that a critical code injection vulnerability in the open‑source AI‑workflow platform Langflow is being actively exploited in the wild.
The flaw, tracked as CVE‑2025‑3248 with a CVSS severity score of 9.8/10.0, allows unauthenticated remote attackers to execute arbitrary code on exposed Langflow servers, effectively giving them full control over the underlying system.
CVE‑2025‑3248 is a missing‑authentication and code‑injection defect in Langflow’s /api/v1/validate/code endpoint, which is used to validate Python code snippets submitted by users.
Internally, Langflow parses the supplied code into an abstract syntax tree (AST), compiles it, and runs it using exec(), all before verifying the identity or permissions of the requestor.
Because decorators and default arguments in Python are evaluated at parse time, attackers can embed malicious payloads inside these constructs, triggering code execution as soon as the server processes the request even without calling the decorated function.
Langflow versions prior to 1.3.0 are affected, and the vulnerability enables unauthenticated remote code execution (RCE) with the privileges of the Langflow process, often at or near system level.
This gives adversaries the ability to deploy malware, open reverse shells, or pivot laterally into internal networks, particularly in environments where Langflow is exposed to the internet or placed in development‑facing segments.
How CISA is framing the risk
CISA added CVE‑2025‑3248 to its Known Exploited Vulnerabilities (KEV) catalog on May 5, 2025, explicitly stating that it has observed evidence of active exploitation.
The agency flagged the bug as “easily exploitable” and urged organizations to prioritize patching, while also requiring U.S. federal agencies to remediate the vulnerability by May 26, 2025 or justify continued use through compensating controls or mission‑critical exceptions.
Censys‑based internet‑scanning data collected around the time of disclosure identified hundreds of internet‑exposed Langflow instances, with concentrations in the U.S., Germany, Singapore, India, and China.
This broad exposure surface makes the platform an attractive target for commodity botnet operators and financially motivated threat‑actor groups hunting for cloud‑ and AI‑adjacent infrastructure to compromise.
Multiple security vendors report that attackers are leveraging public proof‑of‑concept (PoC) exploit code hosted on GitHub and other repositories to automate mass‑scanning and exploitation of vulnerable Langflow endpoints. One documented campaign, observed by trend‑micro, links CVE‑2025‑3248 to the Flodric (or similar) botnet, in which attackers:
- First identify exposed Langflow servers using reconnaissance tools such as Shodan or FOFA.
- Deliver a malicious payload via the
/api/v1/validate/codeendpoint to obtain a reverse shell. - Run basic reconnaissance commands (e.g.,
whoami, network‑config checks) and exfiltrate the output to a command‑and‑control (C2) server.
Infected systems are then typically enlisted into botnets for distributed denial‑of‑service (DDoS) attacks, crypto‑mining, or further lateral‑movement operations inside the breached organization’s environment.
Recommended mitigations and remediation
CISA and vendor advisories consistently recommend the following actions for organizations using Langflow:
- Upgrade immediately to Langflow 1.3.0 or later, in which the vulnerable
/api/v1/validate/codeendpoint has been either hardened or removed and authentication is properly enforced. - Restrict network exposure: If upgrading is not immediately possible, place Langflow behind a firewall, limit access to trusted IP ranges, and avoid exposing the
/apiendpoints directly to the internet. - Monitor for suspicious activity: Hunt for anomalous HTTP requests targeting
/api/v1/validate/codeor/api/v1/build_public_tmp/, and inspect outbound connections from Langflow hosts for beaconing to unknown C2 infrastructure. - Rotate credentials and review permissions: Assume any exposed instance prior to 1.3.0 may already be compromised, and rotate API keys, service accounts, and SSH credentials reachable from the affected server.
The Langflow case underscores the growing risk of unauthenticated RCE in AI‑development and workflow platforms, where powerful code‑execution semantics are exposed through simple web APIs.
As more organizations adopt no‑code and low‑code AI builders, security teams must treat these tools with the same rigor as traditional web applications, ensuring strict authentication, input validation, and runtime sandboxing around any code‑evaluation features.
In the medium term, CISA and commercial threat‑intelligence providers expect to see additional Langflow‑related CVEs enter active exploitation, including newer issues such as CVE‑2026‑33017 and CVE‑2025‑34291, each of which involves similar missing‑authentication or code‑injection patterns.
For now, however, the immediate priority remains ensuring that all Langflow deployments—especially those internet‑facing are patched against CVE‑2025‑3248 before threat actors turn them into fully owned entry points.
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