CVE-2026-22444: apache software foundation apache solr Improper Input Validation

Vulnerability summary

CVE-2026-22444 is a high (CVSS 7.1) Improper Input Validation vulnerability in apache software foundation apache solr. EPSS estimates a 0.69% chance of exploitation in the next 30 days, higher than 51.7% of scored vulnerabilities.

Timeline

1. 21-01-2026
   PublishedVulnerability first disclosed.
2. 21-01-2026
   Last modifiedVulnerability information updated.

Description

The "create core" API of Apache Solr 8.6 through 9.10.0 lacks sufficient input validation on some API parameters, which can cause Solr to check the existence of and attempt to read file-system paths that should be disallowed by Solr's "allowPaths" security setting https://https://solr.apache.org/guide/solr/latest/configuration-guide/configuring-solr-xml.html#the-solr-element .  These read-only accesses can allow users to create cores using unexpected configsets if any are accessible via the filesystem.  On Windows systems configured to allow UNC paths this can additionally cause disclosure of NTLM "user" hashes. Solr deployments are subject to this vulnerability if they meet the following criteria: * Solr is running in its "standalone" mode. * Solr's "allowPath" setting is being used to restrict file access to certain directories. * Solr's "create core" API is exposed and accessible to untrusted users.  This can happen if Solr's RuleBasedAuthorizationPlugin https://solr.apache.org/guide/solr/latest/deployment-guide/rule-based-authorization-plugin.html is disabled, or if it is enabled but the "core-admin-edit" predefined permission (or an equivalent custom permission) is given to low-trust (i.e. non-admin) user roles. Users can mitigate this by enabling Solr's RuleBasedAuthorizationPlugin (if disabled) and configuring a permission-list that prevents untrusted users from creating new Solr cores.  Users should also upgrade to Apache Solr 9.10.1 or greater, which contain fixes for this issue.

• CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.