CriticalCVE-2025-3248

    Langflow < 1.3.0 Unauthenticated RCE via /api/v1/validate/code (CVE-2025-3248)

    Published Last modified In CISA KEV since Sources: pwn.watch, CVE.org, OSV, SingCERT

    What is affected, what to do

    The vulnerability CVE-2025-3248 allows a remote, unauthenticated attacker to execute arbitrary code via crafted HTTP requests due to a missing authentication in Langflow's /api/v1/validate/code endpoint. It is actively exploited in ransomware campaigns since May 2025 and affects Langflow versions prior to 1.3.0. Affected packages on PyPI include versions from 0.0.86 to 0.6.11. An immediate update to version 1.3.0 or higher is urgently required to mitigate the risk.

    The vulnerability is being actively exploited; treat it as a priority. CISA lists it as used in ransomware campaigns. Update Langflow to version 1.3.0. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Langflow lt *..1.3.0
    Fixed in
    • Langflow 1.3.0

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    9.8

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    9.8

    CVSS v3

    Severity Critical on the scale from 0 to 10.

    Source: pwn.watch, CVE.org, OSV, SingCERT

    99.99 %

    EPSS score

    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.

    Source: FIRST EPSS, percentile 99.99

    Show all metrics
    Severity
    Critical
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    262.51 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    actively exploitedSource: VulnCheck KEV (opens in a new tab), CSA/SingCERT How we classify
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    9.8 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    9.8
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    99.99 %
    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    99.99
    Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    Actively exploited
    Published
    In CISA KEV since

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-306

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This CVE is on KEV, flagged for ransomware campaign use, and sits among the CVEs with the highest exploitation likelihood on the entire list. The attack prerequisites are trivial: network-reachable, no authentication, no user interaction, direct RCE impact. Any Langflow instance below 1.3.0 exposed to the internet should be treated as already compromised or about to be — P1, isolate immediately. Internal-only instances behind an auth proxy are less acute but still high priority: Langflow typically holds LLM API keys and cloud credentials, so a compromised host is a reliable pivot into the broader cloud environment.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Upgrade every Langflow instance to version 1.3.0 or later — this is the vendor fix for the unauthenticated /api/v1/validate/code endpoint.
      • Until patched: take Langflow off the public internet. Perimeter firewall or reverse-proxy ACL that restricts inbound traffic to the Langflow port (default 7860) to defined internal source ranges only.
      • Place a reverse proxy (nginx, Traefik, HAProxy) in front and hard-block /api/v1/validate/code with a location directive (return 403) until the upgrade is live.
      • Compromise assessment: inspect each Langflow host for unexpected child processes of the Python/Uvicorn worker (sh, bash, curl, wget, python -c, crypto miners, reverse shells). On any hit, isolate and preserve forensically — do not just restart.
      • Rotate every credential reachable from the Langflow host: LLM provider API keys (OpenAI, Anthropic, Azure OpenAI, HuggingFace), database credentials, vector-DB tokens, cloud IAM keys. For container deployments also rotate workload identities and service-account tokens.
      • Lock down egress from the Langflow host: allow outbound only to required LLM APIs, temporarily block everything else (pastebin/IP-logger services, Tor exits, known mining pools).

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: put Langflow in its own VLAN/subnet with an explicit allowlist. No direct reach into production systems, no database connections outside the dedicated app DB.
      • WAF rule at the reverse proxy: block all POSTs to /api/v1/validate/code outright, or at minimum restrict them to authenticated sessions. Additionally filter obvious Python payload markers in the body (__import__, subprocess, os.system, eval(, compile().
      • Enforce authentication: front Langflow with an auth proxy (oauth2-proxy, Authelia, Entra ID Application Proxy). No Langflow instance should be network-reachable without a prior auth boundary.
      • Container hardening: run Langflow non-root, read-only filesystem, --cap-drop=ALL, seccomp profile. On Kubernetes: NetworkPolicy allowing ingress only from the auth proxy and egress only to LLM endpoints.
      • Least privilege for stored credentials: cap LLM API keys with budget limits, trim cloud IAM roles to the absolute minimum. No S3 bucket or secrets-manager access from the Langflow workload.
      • Resource monitoring: alert on sustained CPU spikes (mining), unusual outbound bandwidth, and newly opened listening sockets on the Langflow host.

    3. Runbook step 3

      Detection rules

      • Web/reverse-proxy access logs: every POST to /api/v1/validate/code without a valid auth session is suspect. SIEM query (Splunk shape): index=web uri_path="/api/v1/validate/code" method=POST | stats count by src_ip, http_user_agent.
      • Sysmon EID 1 / auditd execve: child processes under the Python/Uvicorn parent matching sh, bash, curl, wget, nc, python -c, perl -e. Sigma shape: parent_image|endswith: 'python' AND image|endswith: ('sh','bash','curl','wget','nc').
      • Network telemetry (Zeek/Suricata): outbound connections from the Langflow host to previously unseen external IPs, especially on ports 4444, 1337, 8080, 9999, or to mining-pool DNS names (*.minexmr, *.nanopool, *.supportxmr).
      • EDR process ancestry: Python spawns a shell that in turn runs base64 -d, /dev/tcp/ redirects or curl | sh — the classic loader pattern that follows this code-injection flaw.
      • File monitoring: new executable-bit files in /tmp, /var/tmp, /dev/shm written by the Langflow process. auditd rule: -w /tmp -p wa -k langflow_write.

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    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.

    Source: pwn.watch, cvelistv5, NVD (NIST), CISA KEV Catalog, OSV (Open Source Vulnerabilities), CVE.org (MITRE), CSA/SingCERT

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    langflow-ailangflow
    • < 1.3.0
    • 1.3.0
    langflowlangflow
    • < 1.3.0
    • 1.3.0
    pypilangflow
    • 0.3.1
    • 1.0.10
    • 0.0.61
    • 0.5.0b0
    • 0.6.6
    • 1.0.0a57
    • 0.0.73
    • 1.0.0a9
    • 0.2.13
    • 0.2.8
    • 0.5.0b5
    • 0.0.63
    • 0.6.5a13
    • 1.0.19.post2
    • 1.0.17
    • 1.0.0a34
    • 0.0.72
    • 1.0.0
    • 0.5.11
    • 1.1.4.post1
    • 0.5.0a6
    • 0.6.2
    • 1.0.5
    • 1.0.3
    • 1.1.2
    • 0.5.6
    • 0.5.4
    • 0.2.3
    • 0.1.2
    • 0.0.83
    • 0.3.4
    • 1.0.8
    • 1.0.16
    • 1.0.0a56
    • 0.0.44
    • 0.0.32
    • 0.0.65
    • 0.0.87
    • 0.1.0
    • 1.0.0a44
    • 0.6.8
    • 0.4.18
    • 1.0.0rc0
    • 1.0.0a4
    • 0.4.21
    • 0.5.9
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    Vendors and products

    Weakness classes (CWE)

    • CWE-306Missing Authentication for Critical Function

      Base

      The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

      Entry at MITRE CWE-306

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited
    CSA/SingCERTActive Exploitation of Critical Vulnerability in Langflow (opens in a new tab)CSA/SingCERTactively exploited
    Reference tagged as exploithorizon3.ai (opens in a new tab)PoC (publicly reported)reported, not verified—
    PoC-in-GitHub (nomi-sec)CVE-2025-3248 (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)langflow-exploit (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)exposecheck (opens in a new tab)github.comPoC (publicly reported)reported, not verified

    References & sources

    • github.comlangflow-ai/langflow/security/advisories/GHSA-rvqx-wpfh-mfx7web
    • NVD (NIST)NVD: CVE-2025-3248advisory, pwn-watch
    • github.comlangflow-ai/langflow/pull/6911web, Issue tracking
    • github.comlangflow-ai/langflow/commit/faac4db133de32fcb6d483fa9ff52f40ce4…web
    • github.comlangflow-ai/langflowpackage
    • github.comlangflow-ai/langflow/releases/tag/1.3.0web, Release notes
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2025-3248web, government-resource
    • horizon3.aiattack-research/disclosures/unsafe-at-any-speed-abusing-python-…web
    • vulncheck.comadvisories/langflow-unauthenticated-rceweb, Third-party advisory
    • pypi.orgproject/langflow-basepackage, web
    • GitHub Security Advisoriesadvisories/GHSA-rvqx-wpfh-mfx7advisory
    • horizon3.aiattack-research/disclosures/unsafe-at-any-speed-abusing-python-…Exploit
    • pwn.watchpwn.watch: Langflow: Missing Authentication Vulnerabilitypwn-watch
    • GitHub Security AdvisoriesLangflow advisory: Langflowpwn-watch
    • cisa.govCISA Known Exploited Vulnerabilities Catalogpwn-watch
    • github.compypa/advisory-database/tree/main/vulns/langflow-base/PYSEC-2026…web

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedVulnCheck

      Show 13 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2025/3xxx/CVE-2025-3248.json">CVE-2025-3248</a>
      Referenceadded
      —
      https://github.com/langflow-ai/langflow/pull/6911
      Referenceadded
      —
      https://github.com/langflow-ai/langflow/releases/tag/1.3.0
      Referenceadded
      —
      https://www.horizon3.ai/attack-research/disclosures/unsafe-at-any-speed-abusing-python-exec-for-unauth-rce-in-langflow-ai/
      Referenceadded
      —
      https://www.vulncheck.com/advisories/langflow-unauthenticated-rce
      Referenceremoved
      https://github.com/langflow-ai/langflow/pull/6911
      —
      Referenceremoved
      https://github.com/langflow-ai/langflow/releases/tag/1.3.0
      —
      Referenceremoved
      https://www.horizon3.ai/attack-research/disclosures/unsafe-at-any-speed-abusing-python-exec-for-unauth-rce-in-langflow-ai/
      —
      Referenceremoved
      https://www.vulncheck.com/advisories/langflow-unauthenticated-rce
      —
      Reference typeremoved
      https://github.com/langflow-ai/langflow/pull/6911 Types: Patch
      —
      Reference typeremoved
      https://github.com/langflow-ai/langflow/releases/tag/1.3.0 Types: Release Notes
      —
      Reference typeremoved
      https://www.horizon3.ai/attack-research/disclosures/unsafe-at-any-speed-abusing-python-exec-for-unauth-rce-in-langflow-ai/ Types: Exploit, Third Party Advisory
      —
      Reference typeremoved
      https://www.vulncheck.com/advisories/langflow-unauthenticated-rce Types: Third Party Advisory
      —

      Source identifier: disclosure@vulncheck.com

    2. Record modifiedCISA ADP

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-3248
      Referenceremoved
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-3248
      —
      Reference typeremoved
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-3248 Types: US Government Resource
      —

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Linked advisories

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