XSS in Pi-Hole Web
CVE-2026-33404
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, client hostnames and IP addresses from the FTL database are rendered into the DOM without escaping in network.js (Network page) and charts.js/index.js (Dashboard chart tooltips). While upstream validation in dnsmasq and FTL blocks HTML characters via normal DHCP/DNS paths, the web UI performs no output escaping — an inconsistency with other fields in the same file that are properly escaped. This vulnerability is fixed in 6.5.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.001 (4.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 3.4 (Low). Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N.
Affected products
- Pi-hole Web — versions >= 6.0, < 6.5
- Pi-hole Web_interface
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Third Party Advisory)
Frequently asked questions
- What is CVE-2026-33404?
- CVE-2026-33404 is a low-severity vulnerability in Pi-Hole Web, classified under Cross-site Scripting. CVSS score: 3.4/10. Published 2026-04-06.
- How severe is CVE-2026-33404?
- Low severity. CVSS v3 base score is 3.4 out of 10.