CVE-2026-5027: The 'POST /api/v2/files' endpoint does not sanitize the 'filename' parameter from the multipart form data, all

Q: How do I fix CVE-2026-5027?

langflow: upgrade to 1.9.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-5027 being exploited?

CVE-2026-5027 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-5027 affect?

CVE-2026-5027 affects langflow. Severity is high (CVSS 8.8). The 'POST /api/v2/files' endpoint does not sanitize the 'filename' parameter from the multipart form data, allowing an attacker to write files to arbitrary locations on the filesystem using path traversal sequences ('../').

Q: How urgent is CVE-2026-5027?

Priority 60/100. High severity; EPSS top 1%: very likely to be exploited; Public exploit reference

This week

HIGH 8.8UPGRADE

CVE-2026-5027 is a high-severity flaw (CVSS 8.8) affecting langflow. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The 'POST /api/v2/files' endpoint does not sanitize the 'filename' parameter from the multipart form data, allowing an attacker to write files to arbitrary locations on the filesystem using path traversal sequences ('../').

Why this priority

High severity
EPSS top 1%: very likely to be exploited
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	40.0% (top 1%)
CISA exploited list	No
Weakness	CWE-22
Published	2026-03-27
Last modified	2026-08-18

Publisher (CNA): Tenable Network Security, Inc. · Vendor: langflow

Last updated 2026-08-18 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-27 15:17 UTCPublished CVE record published
2026-08-18 18:00 UTCUpdated Record last modified

langflow langflow UPGRADE

Affected: < 1.9.0

Fixed in: 1.9.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy langflow || rpm -q langflow || langflow --version

2. UPGRADE to 1.9.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade langflow

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade langflow

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Exact fixes by distribution

Fedora ELN · perl-Encode · FIXED · 3.25-528.eln159 · FEDORA-2026-79991d0238 · source

sudo dnf upgrade --advisory=FEDORA-2026-79991d0238

Fedora 46 · fonttools · FIXED · 4.68.0-1.fc46 · FEDORA-2026-65d6c01c75 · source

sudo dnf upgrade --advisory=FEDORA-2026-65d6c01c75

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: yahiahamza/CVE-2026-5027 (4 stars)
GitHub PoC: EQSTLab/CVE-2026-5027 (3 stars)
GitHub PoC: yym8538/CVE-2026-5027 (1 stars)
Exploit-DB: Langflow 1.8.4 - Path Traversal to Remote Code Execution
Nuclei scan template: Langflow <= 1.8.4 - Path Traversal to RCE via File Upload

Advisories and coverage

Research and news

Mandiant / Google Cloud Threat Intel: Vulnerability Discovery and Exploitation Trends in the AI Era 2026-09-30

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-5027?

langflow: upgrade to 1.9.0. Exact commands for each OS are on this page.

Is CVE-2026-5027 being exploited?

CVE-2026-5027 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-5027 affect?

CVE-2026-5027 affects langflow. Severity is high (CVSS 8.8). The 'POST /api/v2/files' endpoint does not sanitize the 'filename' parameter from the multipart form data, allowing an attacker to write files to arbitrary locations on the filesystem using path traversal sequences ('../').

How urgent is CVE-2026-5027?

Priority 60/100. High severity; EPSS top 1%: very likely to be exploited; Public exploit reference

Related CVEs

CVE-2026-34046 HIGH 8.8 UPGRADE UPGRADE Langflow is a tool for building and deploying AI-powered agents and workflows
CVE-2026-6542 MEDIUM 6.5 UPGRADE IBM Langflow OSS 1.0.0 through 1.8.4 could allow any user to supply a flow_id to read transaction logs and ver
CVE-2026-7524 CRITICAL 9.8 UPGRADE IBM Langflow OSS 1.0.0 through 1.9.1 could allow remote code execution due to improper validation of symbolic
CVE-2026-48519 CRITICAL 9.6 UPGRADE Langflow is a tool for building and deploying AI-powered agents and workflows
CVE-2026-33760 HIGH 8.8 UPGRADE Langflow is a tool for building and deploying AI-powered agents and workflows

References

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