CVE-2026-78145: CTFd __init__.py _is_safe_url redirect

Published Aug 23, 2026
·
Updated

A vulnerability has been found in CTFd up to 3.8.4. The affected element is the function issafeurl 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.

Affected Software

1 affected component
CTFd CTFd<=3.8.4

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade CTFd to a version that resolves this vulnerability.

    Patch 5d8515842fd1ab2c3a9f2dde9ffca907aa334ea9

Event History

Aug 23, 2026
CVE Published
via MITRE·10:45 PM
Data Sourced
via MITRE·10:45 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·11:16 PM
DescriptionSeverityWeakness

Frequently Asked Questions

1

Which CTFd deployments are affected?

CTFd versions up to and including 3.8.4 are affected. The issue is in the _is_safe_url function in CTFd/utils/validators/__init__.py.

2

What does an attacker need to exploit this issue?

The attack can be launched remotely and does not require privileges. Exploitation requires a user to interact with a manipulated Next argument, resulting in a redirect to an attacker-controlled destination.

3

Is public exploit information available?

Yes. The exploit has been publicly disclosed and may be used.

4

What should be done to remediate the issue?

Upgrade the affected CTFd component to a version containing patch 5d8515842fd1ab2c3a9f2dde9ffca907aa334ea9.

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203