Cross-site Scripting vulnerabilities in Neos

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

not scored

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

It has been discovered that Neos is vulnerable to several XSS attacks. Through these vulnerabilities, an attacker could tamper with page rendering, redirect victims to a fake login page, or capture user credentials (such as cookies). With the potential backdoor upload an attacker could gain access to the server itself, to an extent mainly limited by the server setup. Reflected Cross-Site Scripting (SXSS) with authentication A Neos backend user with permission to modify content can insert JavaScript instructions into content elements. The browser will execute the script in "Print" preview mode. A Neos backend user who can modify his profile information ("Title", "First Name", "Last name", "Middle Name", "Other Name") can inject JavaScript instructions in those parameters. Once set up, an administrator who wants to edit this user account will execute the code. Both attack vectors require a valid Neos backend user account. Reflected Cross-Site Scripting (RXSS) without authentication A…

Published by the source

17 May 2024, 23:04 UTC

Last modified by the source

17 May 2024, 23:04 UTC

Source last checked

26 Oct 2026, 14:24 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-6cj3-rc4p-f38f

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# Patch Next advisory brief: GHSA-6cj3-rc4p-f38f

Advisory: Cross-site Scripting vulnerabilities in Neos
IDs: GHSA-6cj3-rc4p-f38f
Record: https://patchnext.com/advisories/ghsa-6cj3-rc4p-f38f (revision 1, source checked 26 Oct 2026, 14:24 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: neos/neos 2.0.4, 1.2.13. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist neos/neos: affected >= 1.2.0, < 1.2.13; >= 2.0.0, < 2.0.4; fixed in 2.0.4, 1.2.13

## Suggested inspection (read-only)
- Packagist neos/neos: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on neos/neos.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-6cj3-rc4p-f38f (GitHub-reviewed advisory GHSA-6cj3-rc4p-f38f lists affected ranges: Packagist neos/neos >=1.2.0 =2.0.0 <2.0.4)

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