XSS in Pi-Hole Web
CVE-2026-33403
Pi-hole Admin Interface is a web interface for managing Pi-hole, a network-level ad and internet tracker blocking application. From 6.0 to before 6.5, a reflected DOM-based XSS vulnerability in taillog.js allows an unauthenticated attacker to inject arbitrary HTML into the Pi-hole admin interface by crafting a malicious URL. The file query parameter is interpolated into an innerHTML assignment without escaping. Because the Content-Security-Policy is missing the form-action directive, injected <form> elements can exfiltrate credentials to an external origin. This vulnerability is fixed in 6.5.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (23.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 23.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- Pi-Hole Web — versions >= 6.0, < 6.5
- Pi-Hole Web Interface
Weakness classification (CWE)
References
- github.com/pi-hole/web/security/advisories/GHSA-7xqw-r9pr-qv59 (Vendor Advisory)
Frequently asked questions
- What is CVE-2026-33403?
- CVE-2026-33403 is a medium-severity vulnerability in Pi-Hole Web, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-04-06.
- How severe is CVE-2026-33403?
- Medium severity. CVSS v3 base score is 6.1 out of 10.