CVE-2025-27801Public exploitNetwork attack vector

Stored XSS via script-bearing SVG media preview

Published Jul 28, 2025 · Updated Nov 3, 2025

Stored XSS in Optimizely CMS 11 and 12 allows remote authenticated users to execute JavaScript in a victim's browser. ContentReference document uploads accept SVG files containing scripts, and the media preview serves them so the browser executes the embedded code at its direct URL. Exploitation requires at least the WebEditor role and a victim to open the uploaded preview URL, exposing the browser session to attacker-controlled script behavior.

CVSS severity4.6
Medium
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Optimizely CMS 11 and 12 allows remote authenticated users to execute JavaScript in a victim's browser. ContentReference document uploads accept SVG files containing scripts, and the media preview serves them so the browser executes the embedded code at its direct URL. Exploitation requires at least the WebEditor role and a victim to open the uploaded preview URL, exposing the browser session to attacker-controlled script behavior.

The record

CVE
CVE-2025-27801
Published
Jul 28, 2025
Updated
Nov 3, 2025
Vendor
Optimizely
Product
Optimizely Content Management System (CMS)
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 28, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=11.x <11.21.4
  2. Affected versionversion=12.x <12.22.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Optimizely · Optimizely Content Management System (CMS)version=11.x <11.21.4; version=12.x <12.22.1

Published CVSS scores

4.8SEC Consult Vulnerability LabCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
4.6SEC Consult Vulnerability LabCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:N/VI:L/VA:L/SC:L/SI:L/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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