CVE intelligence and bounded remediation

CVE-2020-15098 — Typo3 Typo3 security vulnerability

High CVSS 8.8

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, it has been discovered that an internal verification mechanism can be used to generate arbitrary checksums. This allows to inject arbitrary data having a valid cryptographic message authentication code (HMAC-SHA1) and can lead to various attack chains including potential privilege escalation, insecure deserialization & remote code execution. The overall severity of this vulnerability is high based on mentioned attack chains and the requirement of having a valid backend user session (authenticated). This has been patched in versions 9.5.20 and 10.4.6.

Severity
High
CVSS
8.8 (3.1)
Published
2020-07-29
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-20, CWE-200, CWE-325, CWE-502, CWE-327

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

Unsafe deserialization and object reconstruction

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

Check exposure

  • Inventory serialization formats accepted from requests, queues, caches, files, cookies, and cross-service messages.
  • Trace whether untrusted input can select classes, types, callbacks, constructors, or object hooks during decoding.
  • Identify signing, schema validation, trust-boundary, and compatibility settings for each decoder.

Remediate safely

  • Replace native object deserialization with a data-only format and explicit schema validation.
  • If replacement is not immediate, use a safe decoder with a minimal type allowlist and disable polymorphic or executable hooks.
  • Update the affected library and add inert tests for unknown types, extra fields, malformed nesting, and unsigned data.

Authoritative sources

Complete CVE record and remediation plan

The detailed catalog view below loads this exact record, its source evidence, and the full seven-phase agentic change plan.