What is CVE-2026-33520?

CVE-2026-33520 is a medium-severity vulnerability in Esri Arcgis Server, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-10-26.

How severe is CVE-2026-33520?

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

XSS in Esri Arcgis Server

CVE-2026-33520

There is a reflected cross site scripting vulnerability in Esri Portal for ArcGIS versions 12.1 and prior which may allow a remote, unauthenticated attacker to create a crafted link which when clicked could potentially execute arbitrary JavaScript code in the victim’s browser. A patch is provided for impacted ArcGIS Server software in General Availability and Extended support status, which includes versions 11.5. Other versions are in mature or retired status, which are not patch eligible. Users working with unlisted versions are advised to upgrade and apply the patch.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-10-26 · last modified 2026-10-26.

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

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Esri Arcgis Server

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

www.esri.com/arcgis-blog/products/trust-arcgis/administration/october-2026-arcg…

Frequently asked questions

What is CVE-2026-33520?: CVE-2026-33520 is a medium-severity vulnerability in Esri Arcgis Server, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-10-26.
How severe is CVE-2026-33520?: Medium severity. CVSS v3 base score is 6.1 out of 10.