Detect CVE-2025-34291: Langflow Origin Validation Error Exploitation in Sumo Logic CSE
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
Sumo Detection Query
_sourceCategory=web/access OR _sourceCategory=nginx OR _sourceCategory=apache
| where (%"url.path" matches "/api/v1/*" OR %"url.path" matches "/api/v2/*" OR %"url.path" matches "/flows*" OR %"url.path" matches "/run*" OR %"url.path" matches "/build*")
| where %"http.method" in ("POST","PUT","DELETE","PATCH")
| where %"http.status_code" in ("200","201","202","204")
| where isNull(%"http.referer") OR %"http.referer" = "" OR %"http.referer" = "null" OR (!isNull(%"http.referer") AND !contains(%"http.referer", %"http.host"))
| eval suspicious_origin = if(isNull(%"http.referer") OR %"http.referer" = "", "Missing Referer", if(%"http.referer" = "null", "Null Origin Bypass", "Cross-Origin Mismatch"))
| count by %"client.ip", suspicious_origin, %"url.path"
| where _count >= 3
| sort by _count descSumo Logic query detecting CVE-2025-34291 exploitation patterns by identifying Langflow API requests with anomalous Origin/Referer header characteristics from the same client IP.
Data Sources
Required Tables
False Positives & Tuning
- Programmatic API consumers that do not emulate browser header behavior
- Internal network scanners or vulnerability assessment tools probing Langflow endpoints
- Cross-origin legitimate uses where Referer Policy is set to no-referrer
- Automated flow execution pipelines that call Langflow API from non-browser contexts
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
Unlock Pro Content
Get the full detection package for CVE-2025-34291 including response playbook, investigation guide, and atomic red team tests.