Detect CVE-2025-34291: Langflow Origin Validation Error Exploitation in CrowdStrike LogScale
Detects exploitation of CVE-2025-34291, an origin validation error (CWE-346) in Langflow that allows attackers to bypass origin checks. This vulnerability is actively exploited in the wild (CISA KEV) and may enable unauthorized access to Langflow API endpoints, flow execution, or administrative functions by bypassing cross-origin restrictions.
MITRE ATT&CK
LogScale Detection Query
#event_simpleName=NetworkReceiveAccept OR #event_simpleName=NetworkConnect
| timestamp := EventTime
| LocalAddressIP4 = LocalAddressIP4
| RemoteAddressIP4 = RemoteAddressIP4
| HttpPath in ("/api/v1/", "/api/v2/", "/flows", "/run", "/build")
| HttpMethod in ("POST", "PUT", "DELETE", "PATCH")
| HttpResponseCode in (200, 201, 202, 204)
| (HttpReferer = null() OR HttpReferer = "" OR HttpReferer = "null" OR NOT HttpReferer matches HostName)
| ProcessName = "python*" OR ProcessName = "uvicorn*" OR ProcessName = "gunicorn*"
| CommandLine matches "langflow*" OR CommandLine matches "*uvicorn app:*"
| eval OriginAnomaly = case(
HttpReferer = null(), "Missing Referer",
HttpReferer = "null", "Null Origin Bypass",
NOT HttpReferer matches HostName, "Cross-Origin Mismatch",
true(), "Legitimate"
)
| where OriginAnomaly != "Legitimate"
| groupBy([RemoteAddressIP4, HttpPath, OriginAnomaly], function=count(1, as=RequestCount))
| where RequestCount >= 3
| sort(RequestCount, order=desc)CrowdStrike Falcon LogScale/CQL query correlating network events and process context to identify Langflow processes receiving cross-origin bypass requests consistent with CVE-2025-34291 exploitation.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate Langflow API integrations using non-browser HTTP clients without Referer headers
- Development workstations running local Langflow instances accessed by automation scripts
- Container-based deployments where inter-service calls lack browser-standard headers
- API gateway configurations that normalize or remove Origin headers before forwarding
Other platforms for CVE-2025-34291
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1CVE-2025-34291 - Missing Origin Header Flow Execution
Expected signal: Web server access log entry with POST to /api/v1/run/FLOW_ID, empty Referer field, HTTP 200 response code, source IP of test machine
- Test 2CVE-2025-34291 - Null Origin Header Bypass Attempt
Expected signal: Web server log showing POST to /api/v1/flows with Origin: null and Referer: null headers, response code 200 or 201
- Test 3CVE-2025-34291 - Cross-Origin Mismatch API Access
Expected signal: Web server log entry with POST to /api/v1/build/ path, Origin and Referer headers showing external domain not matching Langflow host, response code 200-204
- Test 4CVE-2025-34291 - Automated Flow Enumeration Without Origin
Expected signal: Multiple GET requests to Langflow API endpoints within short timeframe from same source IP, all with empty Referer, varying response codes depending on authentication state
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