CVE-2026-22444
Apache Solr 8.6.0 – 9.10.1
Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:NSummary
CVE-2026-22444 is a high-severity Improper Input Validation (CWE-20) vulnerability in Apache Solr. Its CVSS base score is 7.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 48th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-22444 affects the "create core" API in Apache Solr versions 8.6 through 9.10.0, where insufficient input validation on certain API parameters allows Solr to check the existence of and attempt to read filesystem paths that should be disallowed by the "allowPaths" security setting. This issue enables read-only accesses that can permit the creation of cores using unexpected configsets if those are accessible via the filesystem. On Windows systems configured to allow UNC paths, it can additionally lead to the disclosure of NTLM "user" hashes.
The vulnerability can be exploited by low-privileged users (PR:L) with network access (AV:N) in Solr deployments running in standalone mode where the "allowPaths" setting restricts file access and the "create core" API is exposed to untrusted users. This exposure occurs if the RuleBasedAuthorizationPlugin is disabled or if the "core-admin-edit" permission (or equivalent) is granted to non-admin roles. Attackers can achieve high confidentiality impact (C:H) by reading disallowed paths, creating cores with unauthorized configsets, and potentially extracting NTLM hashes on Windows, with low integrity impact (I:L) and no availability impact, as scored at CVSS 7.1 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N) under CWE-20 (Improper Input Validation).
Advisories recommend mitigating by enabling the RuleBasedAuthorizationPlugin if disabled and configuring permissions to prevent untrusted users from creating new Solr cores. Users should also upgrade to Apache Solr 9.10.1 or later, which includes fixes for this issue. Further details are available in the Apache announcement at https://lists.apache.org/thread/qkrb9dd4xrlqmmq73lrhkbfkttto2d1m and the OSS-Security mailing list at http://www.openwall.com/lists/oss-security/2026/01/20/5.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-3665
Vulnerability Data
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"…
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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(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 6 hardening rules · 3 OS baselines
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Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover missing input validation through analysis or test cases.
SI-10 directly requires validity checks on information inputs, structurally preventing improper or missing validation.
Requiring documented development standards and tools can embed input-validation practices into the engineering process.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly require and enforce input validation during development.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.
Secure-coding guidelines and mandatory security testing (including code scans) compel developers to validate and sanitize inputs at design and implementation time, lowering the incidence of malformed or malicious data reaching downstream components.
Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.
Security-by-design principles explicitly call for data validation and sanitization at every layer, reducing the chance that malformed or malicious input will be processed without scrutiny.
Requiring language-specific secure coding standards, peer review, SAST and documented mitigation of common programming errors forces validation of all inputs before they are trusted.
Regular automated validation of system software and data content, combined with scanning of all inbound files, enforces input validation at the boundary before untrusted content is processed.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
RHEL 8 (1 rule)
- V-230265 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-20