---
id: CVE-2026-54567
title: Flask-Reuploaded provides file uploads for Flask
summary: >-
  Flask-Reuploaded provides file uploads for Flask. From 1.5.0 until 1.6.0,
  UploadSet.save(storage, name=...) in src/flask_uploads/flask_uploads.py
  applies lowercase_ext to the default upload path but uses the case-preserving
  extension hel…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-178
  - CWE-434
vendor: jugmac00
product: flask-reuploaded
affected:
  - flask-reuploaded < 1.6.0
patched:
  - Flask-Reuploaded 1.6.0
published: '2026-09-14'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T16:17:09.010'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-54567'
references:
  - url: >-
      https://github.com/jugmac00/flask-reuploaded/commit/5ded76092429c6eb8a4af941b14fbde40a38fff4
    label: security-advisories@github.com
  - url: 'https://github.com/jugmac00/flask-reuploaded/pull/186'
    label: security-advisories@github.com
  - url: >-
      https://github.com/jugmac00/flask-reuploaded/security/advisories/GHSA-937x-gpqr-72gg
    label: security-advisories@github.com
  - url: >-
      https://github.com/jugmac00/flask-reuploaded/security/advisories/GHSA-937x-gpqr-72gg
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://github.com/advisories/GHSA-937x-gpqr-72gg'
tags:
  - nvd
  - cve.org
  - ghsa
  - pip
  - exploit-available
epss: 0.00584
epssPercentile: 0.4662
aliases:
  - GHSA-937x-gpqr-72gg
ecosystem: pip
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-16T15:22:17.514494Z'
ingestedAt: '2026-07-17T20:15:43.245Z'
---

## Overview

Flask-Reuploaded provides file uploads for Flask. From 1.5.0 until 1.6.0, UploadSet.save(storage, name=...) in src/flask_uploads/flask_uploads.py applies lowercase_ext to the default upload path but uses the case-preserving extension helper for a caller-supplied name before extension_allowed evaluates an AllExcept denylist. An attacker who controls the name override can use a mixed-case dangerous extension to bypass a lowercase denylist and store the file in the served upload directory. Exploitation requires a denylist configuration, a user-influenced name override, and a deployment that resolves or executes extensions case-insensitively; pure allowlists remain protected and path containment is not bypassed. On an execution-capable upload directory, the stored file can execute with the web server's privileges and affect confidentiality, integrity, and availability. This issue is fixed in version 1.6.0.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-54567)

Affected packages:

- `Flask-Reuploaded <= 1.5.0`

Patched in:

- `Flask-Reuploaded 1.6.0`

Source: https://github.com/advisories/GHSA-937x-gpqr-72gg