In June 2026, CVE-2026-44825, a vulnerability related to Apache Solr’s Basic Authentication configuration tool, was publicly disclosed. Apache Solr is a widely used open-source search platform for enterprise search, indexing, log analytics, and document retrieval, often serving as critical infrastructure connecting internal applications and data flows.
This vulnerability is not simply the result of authentication being disabled. The core issue is that even when administrators enable Basic Authentication for security purposes, unintended template user accounts may be created during the configuration process. If these accounts are not removed or secured with strong passwords and the Solr Admin interface is exposed to the internet, attackers may be able to validate administrative access through the publicly accessible management interface.
This article examines the technical root cause and attack flow of CVE-2026-44825 and analyzes how publicly exposed Solr Admin assets create attack surfaces, using Criminal IP Asset Search.
CVE-2026-44825: Apache Solr Vulnerability Overview
| Category | Description |
|---|---|
| Vulnerability ID | CVE-2026-44825 |
| Affected Product | Apache Solr |
| Affected Versions | Apache Solr 9.4.0~9.10.1, Apache Solr 10.0.0 |
| Vulnerability Type | Hardcorded Credentials / Insecure Default Initialization |
| Related CWEs | CWE-798, CWE-1188 |
| CVSS Score | 9.8 (Critical) |
| Key Condition | Environment configured with Basic Authentication using “bin/solr auth enable” |
CVE-2026-44825 is an authentication configuration vulnerability that occurs during the process of enabling Basic Authentication in Apache Solr. When administrators use the bin/solr auth enable command in affected versions, template user accounts such as superadmin, admin, search, index may be created alongside the administrator-defined account.
The issue is that these accounts may not have been intentionally created by the administrator. While the authentication setup may appear complete, additional accounts can remain active in the environment. If they are not removed or secured with strong credentials, attackers may attempt to access the Solr cluster using known default credentials. This means that this vulnerability is not caused by the absence of authentication but by a security blind spot introduced during the authentication configuration process. Simply confirming that Basic Authentication is enabled is not sufficient; organizations must also verify actual user accounts and external exposure of the Solr Admin interface.
Technical Root Cause: Template Accounts Created During Basic Authentication Setup
Apache Solr supports Basic Authentication to protect access to management interfaces and APIs. Administrators can quickly enable authentication using the bin/solr auth enable command, eliminating the need to manually create a security.json file.
However, in vulnerable versions, the automated configuration process may create template user accounts in addition to the administrator-specified account. If administrators are unaware of these accounts, authentication may appear enabled while unintended access paths remain available.
The risk unfolds as follows:
- An administrator enables Basic Authentication to secure Solr.
- Additional template user accounts are created during the
bin/solr auth enableprocess. - The administrator may not realize these accounts exist.
- If the Solr Admin interface is publicly accessible, attackers can attempt to authenticate using these accounts.
- Successful authentication may lead to full administrative access to the Solr cluster.
This becomes particularly dangerous because administrators may assume the system is secure simply because authentication has been enabled. In reality, security depends on which users exist in security.json, how strong their passwords are, and whether the Solr Admin interface is exposed externally.
Attack Flow Scenario: From Public Solr Admin Exposure to Administrative Access
An attack leveraging CVE-2026-44825 may proceed as follows:
First, attackers identify publicly accessible Solr Admin interfaces through internet-wide scanning. Page titles, HTTP responses, service banners, and authentication pages can all be used as indicators. The title “Solr Admin” is particularly useful for identifying exposed Solr management interfaces. Once an exposed Solr Admin page is found, attackers verify whether authentication is enabled and determine the authentication mechanism. In some environments, version information may be exposed through endpoints such as /solr/admin/info/system. Even when authentication is enabled, Solr versions can sometimes be inferred from page source code or JavaScript resource parameters.
Attackers then determine whether the identified version falls within the affected range of CVE-2026-44825 and test whether template accounts created during the Basic Authentication setup remain active. If template accounts have not been removed or secured, attackers may gain administrative access to the Solr cluster. Administrative privileges allow access to and modification of collections, cores, schemas, indexed data, and configuration files, potentially leading to search result manipulation, data exposure, and service disruption.
Because Solr is frequently integrated with internal applications, log management systems, document repositories, and databases, attackers may also use indexed data and configuration information to map internal environments and identify follow-on attack paths.
Internet-Exposed Solr Admin Assets Identified Through Criminal IP Asset Search
Apache Solr is generally intended to operate within internal or restricted networks. However, in real-world environments, Solr Admin interfaces are sometimes exposed due to development systems, test environments, temporary cloud deployments, reverse proxy misconfigurations, or missing access controls. Using Criminal IP Asset Search, the following query was used to identify externally accessible Solr Admin assets.
Criminal IP Search Query: title: “Solr Admin”
As of June 2026, a total of 1,154 publicly accessible assets were identified using this query. This indicates that a significant number of Solr Admin management interfaces remain discoverable from the public internet. The query title: "Solr Admin" is an effective method for identifying exposed Apache Solr Admin pages. In some cases, Solr version information may be directly exposed through the management interface or system information endpoints. Even when authentication is enabled, version details may be inferred from JavaScript resources or version parameters embedded in page source code. Attackers can use this information to determine whether a publicly exposed Solr instance falls within the affected range of CVE-2026-44825.
However, these results do not imply that all identified assets are vulnerable to CVE-2026-44825. Actual exposure depends on factors such as the Apache Solr version, the method used to configure Basic Authentication, the user configuration within security.json, and whether template accounts have been removed. Nevertheless, the mere existence of an externally accessible Solr Admin interface provides attackers with an opportunity to identify versions, analyze authentication mechanisms, test default accounts, and search for additional vulnerabilities.
In other words, the results of the title: "Solr Admin" query should not be interpreted as the number of vulnerable systems, but rather as an indicator of how many Solr management interfaces are externally visible and discoverable by attackers.
An analysis of an individual asset identified through Criminal IP demonstrates how publicly exposed Solr Admin interfaces can become practical attack surfaces. The asset was identified through the title: "Solr Admin" query and exposed its Solr Admin management interface over TCP port 80. HTTP banner analysis revealed Apache/2.4.52 (Ubuntu) server information, while version parameters embedded within page resource paths suggested the system was running Solr 9.10.1.
Solr 9.10.1 falls within the affected version range of CVE-2026-44825. However, this alone does not prove the asset is vulnerable. Actual exposure depends on whether bin/solr auth enable was used, whether template accounts remain in security.json, and whether default credentials have been modified. Even so, the example illustrates how attackers can gather valuable intelligence from exposed Solr Admin interfaces. By identifying the management page, examining source code and JavaScript resources, and determining the Solr version, attackers can quickly assess whether the system may be affected by known vulnerabilities.
Criminal IP also classified the asset with a Critical inbound risk rating and identified 19 associated vulnerabilities. This demonstrates how exposed management interfaces, version disclosure, open ports, and known vulnerabilities can combine to create an attractive attack surface for adversaries.
Security Risks of Publicly Exposed Solr Admin Interfaces
An exposed Solr Admin interface is more than just a visible web page. While Solr primarily handles search indexing and query processing, it is often deeply integrated into organizational data flows and business applications.
If attackers obtain Solr administrative privileges, several risks emerge:
Access to Indexed Data
Solr indexes may contain documents, logs, product information, user data, and internal search metadata. Administrative access can provide visibility into sensitive information and underlying data structures.
Search Result Manipulation
When Solr powers search functionality for websites or internal portals, attackers may alter indexes or schemas to manipulate search results, potentially impacting business operations and user trust.
Service Disruption
Administrative access enables attackers to delete collections, modify configurations, or exhaust resources, potentially causing outages that affect critical search-dependent services.
Exposure of Internal Infrastructure
Solr configurations may contain internal hostnames, storage paths, integration details, and authentication settings. Attackers can leverage this information to map internal environments and identify additional attack paths.
Patch Status and Mitigation
The most important aspect of responding to CVE-2026-44825 is validating the actual authentication configuration rather than simply checking the Solr version. Environments that enabled Basic Authentication using bin/solr auth enable should be prioritized for review.
Organizations should verify the following:
- Whether Apache Solr versions 9.4.0–9.10.1 or 10.0.0 are in use
- Whether Basic Authentication was configured using
bin/solr auth enable - Whether template users such as
superadmin,admin,search, orindexexist insecurity.json - Removal of unnecessary template accounts or replacement with strong credentials
- External exposure of the Solr Admin interface and
/solr/admin/info/systemendpoint - Restriction of Solr Admin access through firewalls, VPNs, or access-control policies
- Authentication failure logs, administrative API activity, and configuration change history
- Upgrade planning once fixed versions become available
Version checks alone are not sufficient. Organizations should assess not only known production Solr servers, but also cloud deployments, development systems, testing environments, and temporary assets created for past projects. Any Solr Admin interface accessible from the public internet should be considered a priority review target regardless of confirmed vulnerability status.
FAQ
Q1. If Solr Admin is visible from the internet, does that mean it is vulnerable to CVE-2026-44825?
No. Actual exposure depends on the Solr version and the method used to configure Basic Authentication. However, publicly accessible Solr Admin interfaces make it easier for attackers to identify and assess systems, making them important assets to review.
Q2. If authentication is enabled, is the system safe?
Not necessarily. The core issue behind CVE-2026-44825 is not missing authentication, but the possibility that unintended template accounts remain after authentication is configured. Organizations must review actual user accounts and security.json contents rather than relying solely on the presence of authentication.
Q3. What should organizations do first?
First, determine whether any Solr Admin interfaces are publicly accessible. Then verify the Solr version and authentication configuration. Remove template accounts or replace their credentials with strong passwords, restrict external access to Solr Admin, and ensure that version information is not exposed through system information endpoints or JavaScript resources.
Conclusion
CVE-2026-44825 demonstrates that the presence of authentication alone should not be considered proof of security. Rather than being an authentication bypass issue, it highlights a structural weakness where unintended accounts may remain after authentication is configured. The discovery of 1,154 publicly accessible Solr Admin assets through Criminal IP Asset Search shows that a significant number of Solr management interfaces remain visible to attackers on the public internet. In some environments, version information may also be exposed through /solr/admin/info/system endpoints or JavaScript resources, providing additional clues for attackers to determine whether systems fall within affected version ranges.
This does not mean all exposed assets are vulnerable to CVE-2026-44825. However, exposed management interfaces provide attackers with a starting point for identifying versions, evaluating authentication methods, analyzing account configurations, and searching for additional vulnerabilities. Organizations should not limit their reviews to Solr versions alone. They must assess external exposure, Basic Authentication deployment methods, security.json user configurations, open ports, related vulnerabilities, and historical logs. Attackers rapidly discover exposed management interfaces once vulnerabilities become public. Defenders must identify and understand their attack surface before attackers do.
In relation to this, you can refer to CVE-2026-34197: Apache ActiveMQ RCE Vulnerability Analysis
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Source: Criminal IP(https://www.criminalip.io), SecurityOnline(https://securityonline.info/apache-solr-default-credentials-cve-2026-44825/), NVD(https://nvd.nist.gov/vuln/detail/CVE-2026-44825), Apache oss-security(https://seclists.org/oss-sec/2026/q2/731)
Related Article: https://www.criminalip.io/knowledge-hub/blog/33906