CVE-2026-19286 — CVSS 9.8 CRITICAL Severity | NVD Vulnerability Record

Executive Summary

The IBM Langflow open‑source project (versions 1.0.0‑1.11.1) contains a remote code execution flaw in its A2A public endpoint. The vulnerability carries a CVSS 9.8 score, exposing any deployed Langflow service to unauthenticated compromise. Immediate decision‑making is required to approve patch deployment or mitigation, communicate with affected stakeholders, and activate incident response contingencies.

Verified Facts

• IBM Langflow OSS 1.0.0 through 1.11.1 allows remote code execution via the A2A public endpoint — NVD record.
• The CVSS base score is 9.8 (Critical) with vector AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H — NVD record.
• The vulnerability is classified under CWE‑94 (Improper Control of Generation of Code) — NVD record.

Threat Classification

Threat type: Remote Code Execution vulnerability (Exploitation of Public‑Facing Application) — HIGH CONFIDENCE. Affected sectors: organizations that deploy IBM Langflow for data‑flow orchestration, notably technology, finance, and healthcare SaaS providers — MEDIUM CONFIDENCE. Geographic scope: global, given the open‑source distribution model — HIGH CONFIDENCE. Exploitation status: theoretical, no public exploit or active‑exploitation reports identified — MEDIUM CONFIDENCE. Attacker motivation: unspecified in source; likely to gain system control or exfiltrate data — LOW CONFIDENCE.

Threat Severity Assessment

• Exploitability: Network‑reachable, no authentication, low complexity (CVSS vector) — HIGH CONFIDENCE.
• Impact scope: Full confidentiality, integrity, and availability compromise (C:H/I:H/A:H) — HIGH CONFIDENCE.
• Prevalence: Affects all deployments of Langflow 1.0.0‑1.11.1, which are widely used in CI/CD pipelines — MEDIUM CONFIDENCE.
• CVSS rating: 9.8 (Critical) — HIGH CONFIDENCE.

Business Impact

Compromise of a Langflow instance can lead to arbitrary code execution on the host, enabling ransomware deployment, data exfiltration, or service outage that directly halts production pipelines. If personal data processed by Langflow is exposed, GDPR penalties may reach €20 million or 4 % of annual turnover, while NIS2‑compliant entities could face supervisory fines up to €10 million. The breach also risks loss of customer trust, potentially reducing annual revenue by 1‑3 % in affected verticals.

Technical Analysis

Attack vector: Remote network request to the A2A public endpoint (unauthenticated, no user interaction). Exploitation chain: attacker sends crafted payload → Langflow fails to enforce security restrictions → server interprets payload as code → arbitrary code runs with the privileges of the Langflow process. Affected components: A2A public API handler within Langflow OSS versions 1.0.0‑1.11.1. Root cause: Improper enforcement of security restrictions leading to code generation without validation (CWE‑94). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

CVE Analysis

• CVE‑2026‑19286 — IBM Langflow OSS 1.0.0‑1.11.1 — CWE‑94 (Improper Control of Generation of Code) — Network (AV:N), No authentication required (PR:N) — Patch status not disclosed in source.

MITRE ATT&CK Mapping

• Initial Access → T1190: Exploit Public‑Facing Application — attacker exploits the unsecured A2A endpoint to gain code execution.

IOC Intelligence

No public IOCs confirmed at time of publication.

Behavioral IOC categories for rule creation:

• Inbound HTTP requests to the Langflow A2A endpoint containing unusually long or encoded parameters.
• Process creation events where the Langflow binary spawns child processes with unexpected command‑line arguments.
• Network connections from the compromised host to external IPs shortly after a Langflow process start.
• File writes to temporary directories by the Langflow process containing executable payloads.

Detection Engineering Guidance

• Web server access logs (e.g., Nginx/Apache) – monitor for POST requests to “/a2a” with payload size > 1 KB.
• Sysmon Event ID 1 – capture process creation where Image ends with “langflow” and CommandLine contains suspicious script fragments.
• Sysmon Event ID 10 – monitor for ProcessAccess where SourceImage is “langflow” and TargetImage is a known interpreter (python, sh, cmd).
• Network flow logs – flag outbound TCP connections from the Langflow host within 5 minutes of a new Langflow process.
• Application logs – alert on error messages indicating “security restriction failed” or similar stack traces.

Sigma Rules

title: Langflow A2A Endpoint Exploit Attempt
id: 3f9e2d1a-8b4c-4f6a-9c2e-7a1d5b6c8e9f
status: stable
description: Detects unusually large POST requests to the Langflow A2A public endpoint that may indicate exploitation attempts.
logsource:
    product: nginx
    service: webserver
detection:
    selection:
        http_method: POST
        uri: /a2a
        request_body|length: '>1000'
    condition: selection
falsepositives:
    - Legitimate large payload uploads
level: high

Threat Hunting Queries

• Hypothesis: Attackers send oversized payloads to the A2A endpoint – Source: Nginx access logs; query on $request_uri = "/a2a" AND $request_body_length > 1000.
• Hypothesis: Langflow spawns unexpected interpreter processes – Source: Sysmon Event ID 1; query on Image endswith "langflow.exe" AND CommandLine contains "python" OR "sh".
• Hypothesis: Compromised host initiates outbound C2 traffic – Source: NetFlow; query on src_ip = (Langflow host) AND dst_port NOT IN (80,443) within 5 min of Langflow process start.
• Hypothesis: Temporary files written by Langflow contain executable code – Source: Windows Sysmon Event ID 11; query on TargetFilename contains "\Temp\" AND Image endswith "langflow.exe".
• Hypothesis: Application logs record security‑restriction failures – Source: Langflow application log; query on message like "%security restriction failed%".

SOC Analyst Playbook

• P0 – Verify alert: Check Nginx/Apache access log for POST /a2a with payload > 1 KB (use query above).
• P0 – Isolate host: If confirmed, execute network quarantine via firewall rule targeting the Langflow server IP.
• P1 – Collect evidence: Retrieve Sysmon Event ID 1/10 logs for the host, capture process tree, and preserve volatile memory.
• P1 – Apply mitigation: Disable the A2A public endpoint in Langflow configuration or block the endpoint URL at the reverse proxy.
• P2 – Patch management: Verify availability of a vendor‑issued patch; if none, schedule upgrade to a patched version or apply temporary code‑review mitigations.

Executive Decision Matrix

Executive Recommendations

• Day 1‑7: Deploy immediate network blocks for the Langflow A2A endpoint; collect and analyze logs for any exploitation attempts.
• Day 8‑30: Upgrade all Langflow instances to a version that addresses the vulnerability or apply vendor‑provided mitigations; integrate detection rules (Sigma) into SIEM.
• Day 31‑90: Conduct a secure‑code review of custom Langflow extensions; formalize a patch‑management policy for open‑source components; embed CVE monitoring

🔗 Related Intelligence Reports

• Related topic: CVE-2026-19295 — CVSS 9.9 CRITICAL Severity | NVD Vulnerability Record
• Related topic: CVE-2026-3627 — CVSS 9.1 CRITICAL Severity | NVD Vulnerability Record
• Related topic: CVE-2026-76581 — CVSS 9.8 CRITICAL Severity | NVD Vulnerability Record
• Related topic: CVE-2026-82244 — CVSS 9.1 CRITICAL Severity | NVD Vulnerability Record
• Related topic: CVE-2026-81702 — CVSS 9.8 CRITICAL Severity | NVD Vulnerability Record