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Vulnerability record · CVE-2017-9803 · published 18 September 2017

CVE-2017-9803: Apache solr improper authentication vulnerability

Apache · Solr

Apache Solr's Kerberos plugin can be configured to use delegation tokens, which allows an application to reuse the authentication of an end-user or another application. There are two issues with this functionality (when using SecurityAwareZkACLProvider type of ACL provider e.g. SaslZkACLProvider). Firstly, access to the security configuration can be leaked to users other than the solr super user. Secondly, malicious users can exploit this leaked configuration for privilege escalation to further expose/modify private data and/or disrupt operations in the Solr cluster. The vulnerability is fixed from Apache Solr 6.6.1 onwards.

7.5 CVSS 3.0 High EPSS 2.2% · top 18.2% CWE-287 · Improper authentication
7.5CVSS 3.0 base score, v2 6.0
2.2%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References
17 Jun 2026Last modified by NVD

Description

Apache Solr's Kerberos plugin can be configured to use delegation tokens, which allows an application to reuse the authentication of an end-user or another application. There are two issues with this functionality (when using SecurityAwareZkACLProvider type of ACL provider e.g. SaslZkACLProvider). Firstly, access to the security configuration can be leaked to users other than the solr super user. Secondly, malicious users can exploit this leaked configuration for privilege escalation to further expose/modify private data and/or disrupt operations in the Solr cluster. The vulnerability is fixed from Apache Solr 6.6.1 onwards.

CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://mail-archives.us.apache.org/mod_mbox/www-announce/201709.mbox/%3CCAOOKt53AOScg04zUh0%2BR_fcXD0C9s5mQ-OzdgYdnHz49u
http://www.securityfocus.com/bid/100870 Third Party AdvisoryVDB Entry
http://mail-archives.us.apache.org/mod_mbox/www-announce/201709.mbox/%3CCAOOKt53AOScg04zUh0%2BR_fcXD0C9s5mQ-OzdgYdnHz49u
http://www.securityfocus.com/bid/100870 Third Party AdvisoryVDB Entry

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2017-9803), CISA KEV, FIRST EPSS (scores of 2026-10-02). This page is refreshed as NVD updates the record.