CVE-2026-55779: Silverstripe/versioned Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-m4g4-86qc-v8w7
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CVSS 5.4
CWE-79
Published
Advisory Summary

CVE-2026-55779 is a MODERATE (CVSS 5.4) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Silverstripe/versioned libraries in the Packagist ecosystem. The issue involves silverstripe/versioned has xss in archive admin restore. Remediation is available by upgrading affected packages to version 3.2.1.

CVE-2026-55779 at a Glance

CVE Identifier CVE-2026-55779
GHSA Identifier GHSA-m4g4-86qc-v8w7
Severity MODERATE
CVSS v3.1 Base Score 5.4
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Silverstripe/versioned
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 5.4

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-55779

To remediate this vulnerability, upgrade all affected Silverstripe/versioned dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

silverstripe/versioned fixed: 3.2.1 
Upgrade silverstripe/versioned to 3.2.1
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for silverstripe/versioned

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-55779, inspect your project dependencies for Silverstripe/versioned:

inspect dependencies for silverstripe/versioned

Analyze the terminal output to locate any version of Silverstripe/versioned in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.2.1), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where 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. In Silverstripe/versioned, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact It's possible to use the page title as an XSS vector when restoring a page in ArchiveAdmin ### Reporter Steve Boyd Silverstripe Ltd.

CVE-2026-55779 Affected Silverstripe/versioned Versions

1 component(s)
Fixed Versions:
3.2.1
Product / Package Ecosystem Affected Versions Fixed Version
silverstripe/versioned
 Packagist
< 3.2.1
3.2.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/silverstripe/silverstripe-versioned/security/advisories/GHSA-m4g4-86qc-v8w7
Silverstripe/versioned Source Repository REPOSITORY
https://github.com/silverstripe/silverstripe-versioned/pull/541
Security Fix Commit FIX COMMIT
https://github.com/silverstripe/silverstripe-versioned/commit/6e30a2cf8d4b9233690464da61bd0fc4d3e92952
Silverstripe/versioned Source Repository REPOSITORY
https://github.com/FriendsOfPHP/security-advisories/blob/master/silverstripe/versioned/CVE-2026-55779.yaml
Silverstripe/versioned Source Repository REPOSITORY
https://github.com/silverstripe/silverstripe-versioned
Silverstripe/versioned Release RELEASE
https://github.com/silverstripe/silverstripe-versioned/releases/tag/3.2.1
Silverstripe/versioned Release RELEASE
https://www.silverstripe.org/download/security-releases/cve-2026-55779

Frequently Asked Questions

What is CVE-2026-55779?
CVE-2026-55779 is a security vulnerability in Silverstripe/versioned involving silverstripe/versioned has XSS in archive admin restore under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Silverstripe/versioned versions are affected?
Affected versions include releases prior to 3.2.1 across affected packages: silverstripe/versioned.
What version fixes CVE-2026-55779?
Upgrading to 3.2.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is silverstripe/versioned affected?
Yes, silverstripe/versioned is affected in releases prior to 3.2.1. Upgrade your dependency to 3.2.1 or later.
What is the CVSS score of CVE-2026-55779?
CVE-2026-55779 has a CVSS v3.1 base score of 5.4 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.
What CWE is associated with CVE-2026-55779?
CVE-2026-55779 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (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.).
How can I check Packagist dependencies for CVE-2026-55779?
Run the dependency tree command: 'inspect dependencies for silverstripe/versioned'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-m4g4-86qc-v8w7",
  "modified" : "2026-08-28T22:19:32Z",
  "published" : "2026-08-28T22:19:32Z",
  "aliases" : [ "CVE-2026-55779" ],
  "summary" : "silverstripe/versioned has XSS in archive admin restore",
  "details" : "### Impact\nIt's possible to use the page title as an XSS vector when restoring a page in ArchiveAdmin\n\n### Reporter\nSteve Boyd\nSilverstripe Ltd.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "silverstripe/versioned"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.2.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/silverstripe/silverstripe-versioned/security/advisories/GHSA-m4g4-86qc-v8w7"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/silverstripe/silverstripe-versioned/pull/541"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/silverstripe/silverstripe-versioned/commit/6e30a2cf8d4b9233690464da61bd0fc4d3e92952"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/silverstripe/versioned/CVE-2026-55779.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/silverstripe/silverstripe-versioned"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/silverstripe/silverstripe-versioned/releases/tag/3.2.1"
  }, {
    "type" : "WEB",
    "url" : "https://www.silverstripe.org/download/security-releases/cve-2026-55779"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-08-28T22:19:32Z",
    "nvd_published_at" : null
  }
}