Detect CVE-2025-34291: Langflow Origin Validation Error Exploitation in Google Chronicle
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
YARA-L Detection Query
rule cve_2025_34291_langflow_origin_bypass {
meta:
author = "df00tech Detection Engineering"
description = "Detects CVE-2025-34291 Langflow origin validation error exploitation"
severity = "HIGH"
priority = "HIGH"
reference = "https://nvd.nist.gov/vuln/detail/CVE-2025-34291"
events:
$req.metadata.event_type = "NETWORK_HTTP"
$req.principal.ip = $src_ip
$req.target.url =~ `.*/(api/v1|api/v2|flows|run|build).*`
$req.network.http.method in {"POST", "PUT", "DELETE", "PATCH"}
$req.network.http.response_code in {200, 201, 202, 204}
(
not $req.network.http.referral_url != ""
or $req.network.http.referral_url = "null"
)
match:
$src_ip over 5m
condition:
#req >= 3
}Chronicle YARA-L rule detecting repeated mutating HTTP requests to Langflow API endpoints with absent or null Referer headers, indicative of CVE-2025-34291 origin validation bypass exploitation.
Data Sources
Required Tables
False Positives & Tuning
- Automated Langflow API clients operating without browser-originated requests
- Internal service mesh traffic where headers are stripped by infrastructure components
- Security scanners performing authenticated API enumeration during authorized assessments
- CI/CD pipelines executing Langflow flows as part of ML model deployment processes
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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