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Vulnerability record · CVE-2021-44548 · published 23 December 2021

CVE-2021-44548: Apache solr improper input validation vulnerability

Apache · Solr

An Improper Input Validation vulnerability in DataImportHandler of Apache Solr allows an attacker to provide a Windows UNC path resulting in an SMB network call being made from the Solr host to another host on the network. If the attacker has wider access to the network, this may lead to SMB attacks, which may result in: * The exfiltration of sensitive data such as OS user hashes (NTLM/LM hashes), * In case of misconfigured systems, SMB Relay Attacks which can lead to user impersonation on SMB Shares or, in a worse-case scenario, Remote Code Execution This issue affects all Apache Solr versions prior to 8.11.1. This issue only affects Windows.

9.8 CVSS 3.1 Critical EPSS 5.1% · top 8.0% CWE-20 · Improper input validationCWE-40 · CWE-40
9.8CVSS 3.1 base score, v2 6.8
5.1%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References
17 Jun 2026Last modified by NVD

Description

An Improper Input Validation vulnerability in DataImportHandler of Apache Solr allows an attacker to provide a Windows UNC path resulting in an SMB network call being made from the Solr host to another host on the network. If the attacker has wider access to the network, this may lead to SMB attacks, which may result in: * The exfiltration of sensitive data such as OS user hashes (NTLM/LM hashes), * In case of misconfigured systems, SMB Relay Attacks which can lead to user impersonation on SMB Shares or, in a worse-case scenario, Remote Code Execution This issue affects all Apache Solr versions prior to 8.11.1. This issue only affects Windows.

CVSS:3.1/AV:N/AC:L/PR:N/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
https://security.netapp.com/advisory/ntap-20220114-0005/ Third Party Advisory
https://solr.apache.org/security.html#cve-2021-44548-apache-solr-information-disclosure-vulnerability-through-dataimport Vendor Advisory
https://security.netapp.com/advisory/ntap-20220114-0005/ Third Party Advisory
https://solr.apache.org/security.html#cve-2021-44548-apache-solr-information-disclosure-vulnerability-through-dataimport Vendor Advisory

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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-2021-44548), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.