---
id: CVE-2026-78145
title: A vulnerability has been found in CTFd up to 3.8.4
summary: >-
  A vulnerability has been found in CTFd up to 3.8.4. The affected element is
  the function _is_safe_url of the file CTFd/utils/validators/__init__.py. Such
  manipulation of the argument Next leads to open redirect. The attack can be
  launche…
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N'
cwe:
  - CWE-601
published: '2026-08-23'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T13:10:00.187'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-78145'
references:
  - url: 'https://github.com/CTFd/CTFd/'
    label: cna@vuldb.com
  - url: >-
      https://github.com/CTFd/CTFd/commit/5d8515842fd1ab2c3a9f2dde9ffca907aa334ea9
    label: cna@vuldb.com
  - url: 'https://github.com/CTFd/CTFd/pull/3026'
    label: cna@vuldb.com
  - url: 'https://github.com/CTFd/CTFd/releases/tag/3.8.4'
    label: cna@vuldb.com
  - url: 'https://mblunt.dev/writeups/ctfd-open-redirect/'
    label: cna@vuldb.com
  - url: 'https://vuldb.com/cve/CVE-2026-78145'
    label: cna@vuldb.com
  - url: 'https://vuldb.com/submit/882469'
    label: cna@vuldb.com
  - url: 'https://vuldb.com/vuln/394533'
    label: cna@vuldb.com
  - url: 'https://vuldb.com/vuln/394533/cti'
    label: cna@vuldb.com
tags:
  - nvd
epss: 0.00557
epssPercentile: 0.44929
ingestedAt: '2026-10-14T13:30:58.552Z'
---

## Overview

A vulnerability has been found in CTFd up to 3.8.4. The affected element is the function _is_safe_url of the file CTFd/utils/validators/__init__.py. Such manipulation of the argument Next leads to open redirect. The attack can be launched remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 5d8515842fd1ab2c3a9f2dde9ffca907aa334ea9. Upgrading the affected component is recommended.

## Remediation

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