CVE-2026-55779

Received Received - Intake

Stored XSS in Silverstripe Versioned Module

Publication date: 2026-08-28

Last updated on: 2026-08-28

Assigner: GitHub, Inc.

Description

Silverstripe Versioned provides versioning for Silverstripe models. Prior to 3.2.1, RestoreAction::getRestoreMessage() in src/RestoreAction.php builds ArchiveAdmin restore notifications rendered as CAST_HTML and inserts $restoredItem->Title, $restoredItem->URLSegment, $restoredItem->CMSEditLink(), and $changedProperty['value'] without applying Convert::raw2xml(). When an administrator restores an archived page containing a crafted title or URL segment, the generated restoration message can execute stored JavaScript in the administrator's browser, compromising the confidentiality and integrity of the CMS session. This issue is fixed in version 3.2.1.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-28

Last Modified

2026-08-28

Generated

2026-08-29

AI Q&A

2026-08-29

EPSS Evaluated

N/A

NVD

CVE-2026-55779

Affected Vendors & Products

Vendor	Product	Version / Range
silverstripe	versioned	to 3.2.1 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-79	The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Attack-Flow Graph

Executive Summary

This vulnerability affects Silverstripe Versioned before version 3.2.1. It involves a stored cross-site scripting (XSS) flaw in the RestoreAction::getRestoreMessage() function. When an administrator restores an archived page with a crafted title or URL segment, the system generates a restoration message that executes JavaScript in the administrator's browser without proper sanitization.

Detection Guidance

Check if your Silverstripe Versioned module is below version 3.2.1. Review CMS admin notification messages for any suspicious JavaScript content in page titles or URL segments. Inspect browser console logs for unexpected script execution during page restoration.

Impact Analysis

An attacker could exploit this to steal session cookies, perform actions as the administrator, or manipulate the CMS interface. This compromises the confidentiality and integrity of the CMS session, potentially leading to unauthorized access or data theft.

Compliance Impact

This vulnerability could lead to unauthorized access or data breaches, violating GDPR's integrity and confidentiality requirements. For HIPAA, it may expose protected health information, risking compliance with safeguards for electronic protected health information.

Mitigation Strategies

Upgrade Silverstripe Versioned to version 3.2.1 or later immediately. Review recent CMS activity logs for unauthorized actions. Temporarily disable page restoration functionality if immediate upgrade isn't possible. Monitor admin sessions for suspicious activity.

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