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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 4 Jun 2026.
LangflowApplication

CVE-2025-34291

HIGH · 8.8 CVSS v3.1 Published 2025-12-05
Fix available
A fix is available. Upgrade to after 1.6.9 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild High EPSS Public exploit Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Langflow versions up to and including 1.6.9 contain a chained vulnerability that enables account takeover and remote code execution. An overly permissive CORS configuration (allow_origins='*' with allow_credentials=True) combined with a refresh token cookie configured as SameSite=None allows a malicious webpage to perform cross-origin requests that include credentials and successfully call the refresh endpoint. An attacker-controlled origin can therefore obtain fresh access_token / refresh_token pairs for a victim session. Obtained tokens permit access to authenticated endpoints — including built-in code-execution functionality — allowing the attacker to execute arbitrary code and achieve full system compromise.

In the news

Third-party coverage
Trending covered by 1 outlet this week · latest 1mo ago

Surfaced from public web coverage — external links open in a new tab.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Langflow up to 1.6.9 has a chained vulnerability combining permissive CORS (allow_origins='*' with allow_credentials=True) and insecure refresh token cookies (SameSite=None). This allows cross-origin requests with credentials to the token refresh endpoint, enabling attackers to steal valid tokens and access authenticated API endpoints that include built-in code execution functionality, leading to arbitrary code execution and full system compromise.

MitigationRestrict CORS configuration by removing allow_origins='*' when allow_credentials=True is used, and change the refresh token cookie SameSite attribute from 'None' to 'Lax' or 'Strict' to prevent cross-origin token theft.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
LangflowApplication
Affected:<= 1.6.9

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed Langflow version
    Run 'pip show langflow' or check your package manager to determine the installed version of Langflow
    Affected if The installed version is 1.6.9 or lower
  2. Locate CORS configuration
    Search configuration files (such as config.py, settings.py, or environment variables) for CORS-related settings, specifically 'allow_origins' and 'allow_credentials'
    Affected if allow_origins is set to '*' (wildcard) AND allow_credentials is set to True simultaneously
  3. Examine refresh token cookie configuration
    Search application configuration or source code for the refresh token cookie settings, looking for the 'SameSite' attribute
    Affected if The refresh token cookie is configured with SameSite=None (or the SameSite attribute is missing entirely)
  4. Verify authentication on code execution endpoints
    Review access controls on built-in code execution functionality (such as API endpoints or functions that allow running arbitrary code) to confirm they require valid authentication
    Affected if Code execution endpoints are accessible without proper authentication or accept tokens obtained through the CORS/cookie vulnerability

You are affected if you are running Langflow version 1.6.9 or lower with permissive CORS settings (allow_origins='*' with allow_credentials=True) combined with a SameSite=None refresh token cookie, allowing attackers to steal tokens and access code execution features.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to a release after 1.6.9
Interim mitigation

Restrict CORS configuration by removing allow_origins='*' when allow_credentials=True is used, and change the refresh token cookie SameSite attribute from 'None' to 'Lax' or 'Strict' to prevent cross-origin token theft.

Fix this in Langflow Exploited in the wild — priority engagement
  • Consultation4.0 h
  • Implementation3.0 h
  • Testing6.0 h
  • Review / QA3.0 h
16.0 hours of engineering $2,780
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,448.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-34291 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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