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SolrApplication · Apache

CVE-2020-13957

CRITICAL · 9.8 CVSS v3.1 Published 2020-10-13
Fix available
A fix is available. Upgrade to after 8.6.2 or later.
See remediation →
100/100
Remediation priority · Urgent
High EPSS Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Apache Solr versions 6.6.0 to 6.6.6, 7.0.0 to 7.7.3 and 8.0.0 to 8.6.2 prevents some features considered dangerous (which could be used for remote code execution) to be configured in a ConfigSet that's uploaded via API without authentication/authorization. The checks in place to prevent such features can be circumvented by using a combination of UPLOAD/CREATE actions.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Apache Solr contains an authentication/authorization bypass vulnerability where the security checks designed to prevent dangerous features (capable of remote code execution) from being configured in uploaded ConfigSets can be circumvented by combining UPLOAD and CREATE API actions. This allows unauthenticated attackers to potentially achieve RCE by uploading malicious ConfigSets.

MitigationUpgrade to Apache Solr 8.6.3 or later (or the latest version in each affected branch). If immediate patching is not feasible, disable the ConfigSet upload API or implement network-level access controls to prevent unauthorized access to Solr APIs.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
SolrApplication
Affected:>= 6.6.0, <= 6.6.6>= 7.0.0, <= 7.7.3>= 8.0.0, <= 8.6.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Solr version
    Run 'bin/solr version' or check the Solr admin UI version display. Alternatively, query the Solr API endpoint: curl http://localhost:8983/solr/admin/info/system
    Affected if The installed version falls within 6.6.0-6.6.6, 7.0.0-7.7.3, or 8.0.0-8.6.2
  2. Verify whether Solr authentication is enabled
    Check for the presence of security.json in ZooKeeper (if using SolrCloud) or in the solr home directory. Query the /solr/admin/info/system endpoint without credentials to see if access is granted anonymously
    Affected if No authentication is required to access Solr APIs, meaning the instance is vulnerable to unauthenticated exploitation
  3. Confirm the ConfigSet API is accessible without authentication
    Attempt to invoke the ConfigSet UPLOAD or CREATE API: curl -X POST -H 'Content-Type: application/octet-stream' --data-binary @configset.zip 'http://localhost:8983/solr/admin/configs?action=UPLOAD&name=test&wt=json'
    Affected if The request succeeds without returning an authentication error, indicating the API is exposed and the bypass is possible
  4. Review existing ConfigSets for suspicious content
    List all ConfigSets using: curl 'http://localhost:8983/solr/admin/configs?action=LIST&wt=json'. Inspect any ConfigSets that were not created by trusted administrators, particularly those with modified lib or velocity templates
    Affected if Unexpected or unknown ConfigSets exist that may contain malicious code designed for RCE
  5. Check for recent API activity involving ConfigSet creation or upload
    Review Solr logs for POST requests to /solr/admin/configs with UPLOAD or CREATE actions, focusing on requests from unauthenticated or unexpected IP addresses
    Affected if Log entries show unauthenticated ConfigSet upload or creation events, indicating potential exploitation attempts

A user is affected if they run a vulnerable Solr version (6.6.0-6.6.6, 7.0.0-7.7.3, or 8.0.0-8.6.2) with the ConfigSet API accessible without authentication.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 8.6.2
Interim mitigation

Upgrade to Apache Solr 8.6.3 or later (or the latest version in each affected branch). If immediate patching is not feasible, disable the ConfigSet upload API or implement network-level access controls to prevent unauthorized access to Solr APIs.

Recommended fix High confidence

Solr 8.11.0 (or latest stable 8.x release; fixed in 8.6.3)

  1. 1. Back up your current Solr configuration and data directories
  2. 2. Stop the Solr service
  3. 3. Download Apache Solr 8.11.0 (or latest 8.x stable release) from the official Apache archive
  4. 4. Extract the new Solr distribution to your server
  5. 5. Copy your existing solr.xml and configuration sets from the old installation to the new one
  6. 6. Review and apply any necessary ownership/permissions (typically solr:solr or similar)
  7. 7. Start the Solr service
  8. 8. Verify that the ConfigSet API now properly enforces authorization for UPLOAD/CREATE actions
Caveat Upgrade may require Java version updates (Solr 8.x requires Java 9+); ensure any custom plugins are compatible with the new version; review configuration changes between major versions

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Solr Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-13957 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data