How severe is CVE-2025-34291?

No CVSS score has been assigned to CVE-2025-34291 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2025-34291?

CVE-2025-34291 affects the following packages: langflow (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2025-34291?

Update langflow to 1.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-34291 is resolved across your whole dependency graph.

How do I detect CVE-2025-34291 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for langflow, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-34291 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2025-34291 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-34291 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-34291?

CVE-2025-34291 has an EPSS (Exploit Prediction Scoring System) score of 92.8%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2025-34291 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2025-34291 (Langflow Origin Validation Error Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2026-05-21. CISA required all US federal civilian agencies to remediate this vulnerability by 2026-06-04. The required action was: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2025-34291?

CVE-2025-34291 is classified as CWE-346 (CWE-346). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Is there exploit tooling available for CVE-2025-34291?

A Nuclei detection template exists for CVE-2025-34291, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2025-34291 published, and has it been updated?

CVE-2025-34291 was published on December 5, 2025 and was last updated on October 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

Actively Exploited: CVE-2025-34291: langflow RCE

Exploitation Status

Actively exploited in the wild

Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2026-05-21. Federal agencies were required to remediate by 2026-06-04.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2025-34291.

EPSS Exploitation Probability

via FIRST.org ↗

92.8%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍langflow

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`langflow`	all versions	1.7.0`pip install --upgrade 'langflow==1.7.0'`

Affected Products

1 product · 1 configurations

Application

langflowlangflow

≤ 1.6.9

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for langflow, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update langflow to 1.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-34291 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How to detect CVE-2025-34291

A community-maintained Nuclei template exists for this CVE. You can scan for it directly:

nuclei -id cve-2025-34291 -u https://target

Template: Langflow AI <= 1.6.9 - CORS Misconfiguration
Severity: critical
Impact: An attacker can steal authentication tokens via CORS and execute arbitrary code on the server.
Remediation: Upgrade to Langflow version 1.7.0 or later which restricts CORS origins properly.

Template by ProjectDiscovery nuclei-templates (686f6c61), MIT licensed. View the full template. Scan only systems you are authorised to test.

Frequently Asked Questions

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 bu

O3 Security · Impact-Aware SCA

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CVE-2025-34291 — langflow