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Actively exploitedKnown ransomware use

CVE-2025-3248 Langflow Missing Authentication Vulnerability

Langflow contains a missing authentication vulnerability in the /api/v1/validate/code endpoint that allows a remote, unauthenticated attacker to execute arbitrary code via crafted HTTP requests.

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch nowCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 5 May 2025.
  • CISA lists it as known to be used in ransomware campaigns.
  • Rated Critical severity (CVSS 9.8, scored by Vendor).
  • It has been in the catalogue for 550 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

Langflow versions prior to 1.3.0 are susceptible to code injection in the /api/v1/validate/code endpoint. A remote and unauthenticated attacker can send crafted HTTP requests to execute arbitrary code.

Affected Versions

ProductVersions
langflow-ai langflowbefore 1.3.0

From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for Langflow. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

    Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

    Vulnerability Management
  3. 3

    Hunt for compromise

    If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.

    Incident Response
  4. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsRated critical, so if it affects devices in your Cyber Essentials scope, the update must be installed within 14 days of the vendor releasing it.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 26 May 2025 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

Stay Ahead

More Exploited Langflow Flaws

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CVE-2026-0770Langflow Inclusion of Functionality from Untrusted Control Sphere VulnerabilityAdded 21 Jul 2026CVE-2026-55255Langflow Authorization Bypass Through User-Controlled Key VulnerabilityAdded 7 Jul 2026CVE-2025-34291Langflow Origin Validation Error VulnerabilityAdded 21 May 2026CVE-2026-33017Langflow Code Injection VulnerabilityAdded 25 Mar 2026

All 5 exploited Langflow vulnerabilities

Not Sure If You Are Exposed?

Our attack surface and vulnerability teams can check your internet-facing estate for CVE-2025-3248 and every other exploited flaw on the list.

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Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2025-3248
  3. CVE record: CVE-2025-3248
  4. FIRST EPSS
  5. github.com/langflow-ai/langflow/pull/6911
  6. github.com/langflow-ai/langflow/releases/tag/1.3.0
  7. horizon3.ai/attack-research/disclosures/unsafe-at-any-speed-abusing-python-exec-for-unauth-rce-in-la
  8. vulncheck.com/advisories/langflow-unauthenticated-rce