Open Redirect in Ctfd
CVE-2026-78145
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.
Vulnerability class: Open Redirect
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.006 (44.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 44.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.001
Affected products
- Ctfd — versions 3.8.0, 3.8.1, 3.8.2
Weakness classification (CWE)
References
- vuldb.com/vuln/394533 (technical-description, vdb-entry)
- vuldb.com/vuln/394533/cti (signature, permissions-required)
- vuldb.com/cve/CVE-2026-78145 (third-party-advisory)
- vuldb.com/submit/882469 (third-party-advisory)
- mblunt.dev/writeups/ctfd-open-redirect/ (exploit)
- github.com/CTFd/CTFd/pull/3026 (issue-tracking, patch)
- github.com/CTFd/CTFd/commit/5d8515842fd1ab2c3a9f2dde9ffca907aa334ea9 (patch)
- github.com/CTFd/CTFd/releases/tag/3.8.4 (patch)
- github.com/CTFd/CTFd/ (product)
Frequently asked questions
- What is CVE-2026-78145?
- CVE-2026-78145 is a medium-severity vulnerability in Ctfd, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 4.3/10. Published 2026-08-23.
- How severe is CVE-2026-78145?
- Medium severity. CVSS v3 base score is 4.3 out of 10.