What is CVE-2021-3811?

CVE-2021-3811 is a medium-severity vulnerability in Pi-Hole Pi-Hole/adminlte, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-09-17.

How severe is CVE-2021-3811?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Pi-Hole Pi-Hole/adminlte

CVE-2021-3811

adminlte is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-09-17 · last modified 2026-06-17.

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: 0.005 (44.8th percentile), scored 2026-10-19.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 44.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Pi-Hole Pi-Hole/adminlte — versions unspecified
Pi-Hole Web Interface

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

huntr.dev/bounties/fa38c61f-4043-4872-bc85-7fe5ae5cc2e8 (Exploit, Patch, Third Party Advisory, Issue Tracking)
github.com/pi-hole/adminlte/commit/f526716de7bb0fd382a64bcbbb33915c926f94bb (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-3811?: CVE-2021-3811 is a medium-severity vulnerability in Pi-Hole Pi-Hole/adminlte, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-09-17.
How severe is CVE-2021-3811?: Medium severity. CVSS v3 base score is 6.1 out of 10.