CVE intelligence and bounded remediation

CVE-2020-15099 — Typo3 Typo3 security vulnerability

High CVSS 8.1

In TYPO3 CMS greater than or equal to 9.0.0 and less than 9.5.20, and greater than or equal to 10.0.0 and less than 10.4.6, in a case where 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 the ability 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. This has been patched in versions 9.5.20 and 10.4.6.

Severity
High
CVSS
8.1 (3.1)
Published
2020-07-29
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-20, CWE-200

Affected products

  • typo3 / typo3

Showing 1 representative product identities from 2 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Information disclosure and sensitive data exposure

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace sensitive data through responses, errors, logs, metrics, traces, caches, exports, files, backups, and client bundles.
  • Identify affected subjects, tenants, retention windows, access controls, and downstream copies without opening unnecessary sensitive records.
  • Review metadata, timing, status, length, and existence signals as well as direct content disclosure.

Remediate safely

  • Minimize collection and output, apply field-level authorization and redaction at a centralized boundary, and return generic external errors.
  • Remove secrets and sensitive data from logs, artifacts, URLs, caches, and client-side bundles; rotate credentials that may have been exposed.
  • Update the affected component and add synthetic-data tests for response, error, observability, and export paths.

Authoritative sources

Complete CVE record and remediation plan

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