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High, CVSS 8.1

Exposure of Sensitive Information to an Unauthorized Actor in TYPO3 CMS

CVE-2020-15099GHSA-3x94-fv5h-5q2c

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (typo3/cms-core 10.4.6, 9.5.20; typo3/cms 10.4.6, 9.5.20), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • Packagist typo3/cms-core

    Affected
    >= 9.0.0, < 9.5.20>= 10.0.0, < 10.4.6
    Fixed in
    9.5.20, 10.4.6

  • Packagist typo3/cms

    Affected
    >= 10.0.0, < 10.4.6>= 9.0.0, < 9.5.20
    Fixed in
    9.5.20, 10.4.6

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
8.1 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
  • CVE-2020-15099: 1.79% estimated exploitation activity in the next 30 days; percentile 78.39 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Meta CVSS: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C (7.5) CWE-20, CWE-200 Problem In case an attacker manages to generate a valid cryptographic message authentication code (HMAC-SHA1) - either by using a different existing vulnerability or in case the internal encryptionKey was exposed - it is possible to retrieve arbitrary files of a TYPO3 installation. This includes the possibility to fetch typo3conf/LocalConfiguration.php which again contains the encryptionKey as well as credentials of the database management system being used. In case a database server is directly accessible either via internet or in a shared hosting network, this allows to completely retrieve, manipulate or delete database contents. This includes creating an administration user account - which can be used to trigger remote code execution by injecting custom extensions. Solution Update to TYPO3 versions 9.5.20 or 10.4.6 that fix the problem described. Credits Thanks to TYPO3 security team…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 1 · created ·

    Published from ghsa record GHSA-3x94-fv5h-5q2c

Agent brief

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# Patch Next advisory brief: CVE-2020-15099

Advisory: Exposure of Sensitive Information to an Unauthorized Actor in TYPO3 CMS
IDs: CVE-2020-15099, GHSA-3x94-fv5h-5q2c
Record: https://patchnext.com/advisories/cve-2020-15099 (revision 1, source checked 26 Oct 2026, 14:18 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: typo3/cms-core 10.4.6, 9.5.20; typo3/cms 10.4.6, 9.5.20. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist typo3/cms-core: affected >= 9.0.0, < 9.5.20; >= 10.0.0, < 10.4.6; fixed in 9.5.20, 10.4.6
- Packagist typo3/cms: affected >= 10.0.0, < 10.4.6; >= 9.0.0, < 9.5.20; fixed in 9.5.20, 10.4.6

## Suggested inspection (read-only)
- Packagist typo3/cms-core: check the installed version with your package manager.
- Packagist typo3/cms: 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 typo3/cms-core, typo3/cms.
- 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-3x94-fv5h-5q2c (GitHub-reviewed advisory GHSA-3x94-fv5h-5q2c lists affected ranges: Packagist typo3/cms-core >=9.0.0 =10.0.0 =10.0.0 =9.0.0 <9.5.20)

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