CVE-2026-55442
Tenable Plugin
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AI Threat Summary
CVE-2026-55442 is a moderate vulnerability with a CVSS score of 5.3 affecting the target software. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.
Description
The Goobi viewer is a web application that allows digitised material to be displayed in a web browser. From version 23.03 to before version 26.05, SolrTools.cleanUpQuery() strips Solr local-parameter syntax ({!...}) from user-supplied query strings before they reach Solr. Its regex can be bypassed by wrapping the local parameter in a second pair of curly braces ({{!...}}): the outer braces are stripped, the inner {!...} survives intact, and a valid Solr local parameter is forwarded. The flaw is in the shared sanitizer, so it affects any endpoint that routes user input through cleanUpQuery. The double-brace bypass applies from v23.10 (the greedy \{(.+)\} regex); a related bare-!join rewrap path is present. This issue has been patched in version 26.05.
Attack Chain
Attacker scans for vulnerable versions using version banners or PoC scanners
Attacker triggers CVE-2026-55442 vulnerability with a crafted request or payload
Vulnerability exploited to perform unauthorized actions on the target system
Depending on vulnerability type, attacker achieves data access, service disruption, or code execution
MITRE ATT&CK Techniques
Indicators of Compromise
| Type | Value | Description | |
|---|---|---|---|
| user_agent | Mozilla/5.0 (compatible; exploit/1.0) |
Generic exploit scanner user agent pattern | |
| url | /api/vuln-endpoint?payload=<malicious> |
Exploit attempt against application endpoint — monitor access logs for anomalous params |
Remediation
Quick Facts
| CVE ID | CVE-2026-55442 |
| CVSS Score | 5.3 |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
| Published | 2026-10-23 |
| Exploited | No |
| CISA KEV | No |
| PoC | Not public |