CVE-2026-56095: Insecure Deserialization in extension "Apache Solr for TYPO3 - Enterprise Search" (solr)

Severity: high (CVSS 7.7 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-25 · updated 2026-09-17
Weakness: CWE-502

Description

The extension's indexer passed every field value returned by content object rendering through PHP's unserialize() function when transferring multi-value data for the SOLR_CLASSIFICATION, SOLR_MULTIVALUE and SOLR_RELATION content object types, rather than a safe format. If user-generated content saved in the TYPO3 database can reach an indexed field, this exposes a PHP Object Injection surface.

Affected products

TYPO3 Extension "Apache Solr for TYPO3 - Enterprise Search": from 13.0.0 before 13.1.4; from 12.0.0 before 12.1.4; from 11.5.0 before 11.6.6 — fixed in 11.6.6, 12.1.4, 13.1.4

How to fix

Upgrade to a fixed version: TYPO3 Extension "Apache Solr for TYPO3 - Enterprise Search" 11.6.6, 12.1.4, 13.1.4. Check the vendor advisory for mitigations.

References

https://typo3.org/security/advisory/typo3-ext-sa-2026-025

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