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PatchSiren cyber security CVE debrief

CVE-2026-5027 langflow-ai CVE debrief

The Langflow application, specifically the 'POST /api/v2/files' endpoint, is vulnerable to a path traversal attack due to insufficient sanitization of the 'filename' parameter. This allows an attacker to write files to arbitrary locations on the filesystem. The vulnerability has a CVSS score of 8.8 and is classified as HIGH severity. Affected product deployments should be reviewed for exposure and patched or mitigated accordingly. Organizations using Langflow should prioritize patching this vulnerability to prevent potential arbitrary file writes. The CVE record was published on 2026-03-27T15:17:04.743Z and has not been modified since then. Defenders should verify affected product deployments, review official advisories, and plan vendor-supported updates or mitigations. Compensating controls and monitoring may be necessary for exposed systems. The NVD entry is currently Analyzed.

Vendor
langflow-ai
Product
langflow
CVSS
HIGH 8.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-03-27
Original CVE updated
2026-08-18
Advisory published
2026-03-27
Advisory updated
2026-08-18

Who should care

Langflow users and administrators, security teams responsible for monitoring and protecting against potential arbitrary file writes, and operators of affected platforms should be aware of this vulnerability and take immediate action to patch or mitigate it. Vulnerability management and security teams should prioritize this issue and review compensating controls for exposed systems while remediation is scheduled and verified.

Technical summary

The Langflow application is vulnerable to a path traversal attack due to insufficient sanitization of the 'filename' parameter in the 'POST /api/v2/files' endpoint. This allows an attacker to write files to arbitrary locations on the filesystem. The vulnerability has a CVSS score of 8.8 and is classified as HIGH severity. Affected product deployments should be reviewed for exposure and patched or mitigated accordingly.

Defensive priority

Organizations using Langflow should prioritize patching this vulnerability to prevent potential arbitrary file writes.

Recommended defensive actions

  • Review and apply the vendor's patch for CVE-2026-5027
  • Implement input validation and sanitization for file uploads
  • Monitor for suspicious file system activity
  • Conduct regular vulnerability scans and inventory checks
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE-2026-5027 record indicates a HIGH severity vulnerability with a CVSS score of 8.8. The 'POST /api/v2/files' endpoint in Langflow does not sanitize the 'filename' parameter, allowing path traversal attacks. The NVD entry is currently Analyzed. Defenders should verify affected product deployments, review official advisories, and plan vendor-supported updates or mitigations. Compensating controls and monitoring may be necessary for exposed systems.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-5027 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-5027

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-5027 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-5027

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.