What is CVE-2026-33209?

CVE-2026-33209 is a medium-severity vulnerability in Avo-Hq Avo, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-03-20.

How severe is CVE-2026-33209?

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

XSS in Avo-Hq Avo

CVE-2026-33209

Avo is a framework to create admin panels for Ruby on Rails apps. Prior to version 3.30.3, a reflected cross-site scripting (XSS) vulnerability exists in the return_to query parameter used in the avo interface. An attacker can craft a malicious URL that injects arbitrary JavaScript, which is executed when he clicks a dynamically generated navigation button. This issue has been patched in version 3.30.3.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-03-20 · 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: 0.003 (24.0th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 24th percentile — 24.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.001

Affected products

Avo-Hq Avo — versions < 3.30.3
Avohq Avo

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/avo-hq/avo/security/advisories/GHSA-762r-27w2-q22j (Vendor Advisory)
github.com/avo-hq/avo/pull/4330 (Patch, Issue Tracking)
github.com/avo-hq/avo/commit/4453d39ddc6309f3bc8ada73ef21e1971112de7d (Patch)
github.com/avo-hq/avo/releases/tag/v3.30.3 (Product, Release Notes)

Frequently asked questions

What is CVE-2026-33209?: CVE-2026-33209 is a medium-severity vulnerability in Avo-Hq Avo, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-03-20.
How severe is CVE-2026-33209?: Medium severity. CVSS v3 base score is 6.1 out of 10.