---
title: "CVE-2026-54567: Flask-Reuploaded - Unrestricted File Upload"
description: "Flask-Reuploaded 1.5.0 to <1.6.0 contains a file upload vulnerability caused by inconsistent extension case handling in UploadSet.save, letting attackers bypass lowercase denylist and upload executable files, exploit requires denylist configuration and user-controlled filename."
url: https://panop.io/threat-heartbeat/CVE-2026-54567/
---

# CVE-2026-54567 Flask-Reuploaded - Unrestricted File Upload

Flask-Reuploaded 1.5.0 to <1.6.0 contains a file upload vulnerability caused by inconsistent extension case handling in UploadSet.save, letting attackers bypass lowercase denylist and upload executable files, exploit requires denylist configuration and user-controlled filename.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

EPSS

0.63% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-54567)

## Details

Type

Unrestricted File Upload

Impact

Remote Code Execution, Information Disclosure, Data Tampering, Denial Of Service

CVSS vector

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

Published

14 September 2026

Updated

15 October 2026

Weakness

[CWE-178](https://cwe.mitre.org/data/definitions/178.html)

## Vendor fix

Update to version 1.6.0 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-54567](https://nvd.nist.gov/vuln/detail/CVE-2026-54567)
- [https://github.com/jugmac00/flask-reuploaded/commit/5ded76092429c6eb8a4af941b14fbde40a38fff4](https://github.com/jugmac00/flask-reuploaded/commit/5ded76092429c6eb8a4af941b14fbde40a38fff4)
- [https://github.com/jugmac00/flask-reuploaded/pull/186](https://github.com/jugmac00/flask-reuploaded/pull/186)
- [https://github.com/jugmac00/flask-reuploaded/security/advisories/GHSA-937x-gpqr-72gg](https://github.com/jugmac00/flask-reuploaded/security/advisories/GHSA-937x-gpqr-72gg)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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