GHSA-4f2f-jr2m-j7p4: Duplicate Advisory TYPO3-CORE-SA-2026-021: Broken Access Control Vulnerability
HIGHGHSA-4f2f-jr2m-j7p4 is a HIGH typo3-core-sa-2026-021: broken access control vulnerability (CWE-346: Origin Validation Error) affecting Duplicate Advisory libraries in the Packagist ecosystem. The issue involves typo3-core-sa-2026-021: broken access control in backend and install tool. Remediation is available by upgrading affected packages to version 13.4.34, 14.3.6.
GHSA-4f2f-jr2m-j7p4 at a Glance
How to Fix GHSA-4f2f-jr2m-j7p4
To remediate this vulnerability, upgrade all affected Duplicate Advisory dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade typo3/cms-core to 13.4.34
Upgrade typo3/cms-core to 14.3.6
Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for typo3/cms-core
How to Check if You Are Affected
To determine whether your application is affected by GHSA-4f2f-jr2m-j7p4, inspect your project dependencies for Duplicate Advisory:
inspect dependencies for typo3/cms-core
Analyze the terminal output to locate any version of Duplicate Advisory in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 13.4.34), 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-346: Origin Validation Error, where the product does not properly verify that the source of data or communication is valid. In Duplicate Advisory, 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
GHSA-4f2f-jr2m-j7p4 Affected Duplicate Advisory Versions
2 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
typo3/cms-core
|
Packagist |
≥ 13.0.0
< 13.4.34
|
13.4.34
|
|
typo3/cms-core
|
Packagist |
≥ 14.0.0
< 14.3.6
|
14.3.6
|
References
Frequently Asked Questions
What is GHSA-4f2f-jr2m-j7p4?
Which Duplicate Advisory versions are affected?
What version fixes GHSA-4f2f-jr2m-j7p4?
Is typo3/cms-core affected?
What CWE is associated with GHSA-4f2f-jr2m-j7p4?
How can I check Packagist dependencies for GHSA-4f2f-jr2m-j7p4?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-4f2f-jr2m-j7p4",
"modified" : "2026-09-01T21:30:52Z",
"published" : "2026-08-11T09:32:33Z",
"withdrawn" : "2026-09-01T21:30:52Z",
"aliases" : [ ],
"summary" : "Duplicate Advisory: TYPO3-CORE-SA-2026-021: Broken Access Control in Backend and Install Tool",
"details" : "## Duplicate Advisory\n\nThis advisory has been withdrawn because it is a duplicate of GHSA-68jx-f42c-7599. This link is maintained to preserve external references.\n\n## Original Description\nThe referrer enforcement introduced with TYPO3-CORE-SA-2020-006 (CVE-2020-11069) became ineffective in TYPO3 v13.0, where TYPO3 CMS started serving the backend and Install Tool applications from the site's main entry script instead of the dedicated typo3/ directory.\n\nWhether a request originated from the backend or Install Tool itself was determined by comparing the referrer against the directory of the entry script, which since then is the site root. As a consequence, requests originating from any script running on one of the TYPO3 instance's own domains, such as a frontend page, were accepted by backend routes and Install Tool endpoints.\n\nAttackers able to execute JavaScript on one of those domains, for instance by exploiting a cross-site scripting vulnerability, could invoke these endpoints via Fetch/XHR with the privileges of an authenticated victim's user session. This issue affects TYPO3 CMS versions 13.0.0-13.4.33 and 14.0.0-14.3.5.",
"severity" : [ {
"type" : "CVSS_V4",
"score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Packagist",
"name" : "typo3/cms-core"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "13.0.0"
}, {
"fixed" : "13.4.34"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Packagist",
"name" : "typo3/cms-core"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "14.0.0"
}, {
"fixed" : "14.3.6"
} ]
} ]
} ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-19418"
}, {
"type" : "WEB",
"url" : "https://github.com/TYPO3/typo3/commit/4a75e862c589c85d795d7c65dcdc835f8f413efc"
}, {
"type" : "WEB",
"url" : "https://github.com/TYPO3/typo3/commit/a0e8ee06a40e959b9e7b06a4b1cb19d3a0d3dcf7"
}, {
"type" : "WEB",
"url" : "https://github.com/TYPO3/typo3/commit/ae0abd329d52285fe6e92804c3608820ad45e872"
}, {
"type" : "WEB",
"url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2026-19418.yaml"
}, {
"type" : "WEB",
"url" : "https://news.typo3.com/security/advisory/typo3-core-sa-2026-021"
}, {
"type" : "WEB",
"url" : "https://typo3.org/security/advisory/typo3-core-sa-2020-006"
}, {
"type" : "WEB",
"url" : "https://typo3.org/security/advisory/typo3-core-sa-2026-021"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-346" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2026-09-01T21:30:52Z",
"nvd_published_at" : "2026-08-11T08:17:20Z"
}
}