What’s Vulnerable › Vulnerabilities

CVE-2021-44548: Apache Solr information disclosure vulnerability through DataImportHandler

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 5.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-12-23 · updated 2026-06-17
• Weakness: CWE-20

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.

Affected products

• Apache Software Foundation Apache Solr: before 8.11.1 — fixed in 8.11.1

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache Solr 8.11.1. Check the vendor advisory for mitigations.

References

• https://security.netapp.com/advisory/ntap-20220114-0005/
• https://solr.apache.org/security.html#cve-2021-44548-apache-solr-information-disclosure-vulnerability-through-dataimporthandler
• https://security.netapp.com/advisory/ntap-20220114-0005/
• https://solr.apache.org/security.html#cve-2021-44548-apache-solr-information-disclosure-vulnerability-through-dataimporthandler

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