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CRITICAL severity

CVE-2021-44548 — solr-parent

CRITICAL

CVE-2021-44548 is a critical-severity (CVSS 9.8) Improper Input Validation vulnerability in org.apache.solr:solr-parent. A fix is available for org.apache.solr:solr-parent — see the affected versions and patch details below.

Apache Solr Improper Input Validation and Path Traversal

Also known asBIT-solr-2021-44548GHSA-pccr-q7v9-5f27
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
5.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs93th percentile — riskier than 93% of all scored CVEsHighest risk
4.52%4.92%5.33%5.73%5.0%5.2%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
☕org.apache.solr:solr-parent

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

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 Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.apache.solr:solr-parentall versions8.11.1org.apache.solr:solr-parent:8.11.1

Affected Products

1 product · 1 configurations
Application
solrapache
< 8.11.1
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.solr:solr-parent, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.apache.solr:solr-parent to 8.11.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-44548 is resolved across your whole dependency graph.

  3. Workarounds

    Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

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 version
O3 Security · Impact-Aware SCA

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CVE-2021-44548: solr-parent RCE — Fixed in 8.11.1