What is CVE-2019-17558?

CVE-2019-17558 is a high-severity vulnerability in Apache Solr, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 7.5/10. Published 2019-12-30.

How severe is CVE-2019-17558?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2019-17558 known to be exploited?

Yes. CVE-2019-17558 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 103 public proof-of-concept repositories are indexed.

Vulnerability in Apache Solr

CVE-2019-17558

Apache Solr 5.0.0 to Apache Solr 8.3.1 are vulnerable to a Remote Code Execution through the VelocityResponseWriter. A Velocity template can be provided through Velocity templates in a configset `velocity/` directory or as a parameter. A user defined configset could contain renderable, potentially malicious, templates. Parameter provided templates are disabled by default, but can be enabled by setting `params.resource.loader.enabled` by defining a response writer with that setting set to `true`. Defining a response writer requires configuration API access. Solr 8.4 removed the params resource loader entirely, and only enables the configset-provided template rendering when the configset is `trusted` (has been uploaded by an authenticated user).

Published 2019-12-30 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.986 (99.9th percentile), scored 2026-10-19.

Very high probability of exploitation in the next 30 days — among the top 0.1% most-likely-to-be-exploited CVEs. 100th percentile — 99.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.986 · newest: 0.986 · change: 0.000

Affected products

Apache Solr
Oracle Primavera Unifier — versions 16.1, 16.2, 18.8
Apache Solr — versions Apache Solr 5.0.0 to Apache Solr 8.3.1

Weakness classification (CWE)

CWE-74 — Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection)

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2021-11-03. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2022-05-03.

Required action: Apply updates per vendor instructions.

Public proof-of-concept exploits

References

lists.apache.org/thread.html/rb964fe5c4e3fc05f75e8f74bf6b885f456b7a7750c36e9a80… (mailing-list, Mailing List)
lists.apache.org/thread.html/r9271d030452170ba6160c022757e1b5af8a4c9ccf9e04164d… (mailing-list, Mailing List)
lists.apache.org/thread.html/ra29fa6ede5184385bf2c63e8ec054990a7d4622bba1d244be… (mailing-list, Mailing List)
lists.apache.org/thread.html/r36e35fd76239a381643555966fb3e72139e018d52d76544fb… (mailing-list, Mailing List, Issue Tracking)
lists.apache.org/thread.html/r5074d814d3a8c75df4b20e66bfd268ee0a73ddea7e85070ce… (mailing-list, Exploit, Mailing List)
lists.apache.org/thread.html/rf6d7ffae2b940114324e036b6394beadf27696d051ae0c4a5… (mailing-list, Exploit, Mailing List)
lists.apache.org/thread.html/r58c58fe51c87bc30ee13bb8b4c83587f023edb34901870520… (mailing-list, Mailing List)
lists.apache.org/thread.html/r25f1bd4545617f5b86dde27b4c30fec73117af65598a30e20… (mailing-list, Mailing List)
lists.apache.org/thread.html/r12ab2cb15a34e49b4fecb5b2bdd7e10f3e8b7bf1f4f47fcde… (mailing-list, Mailing List)
lists.apache.org/thread.html/r99c3f7ec3a079e2abbd540ecdb55a0e2a0f349ca7084273a1… (mailing-list, Mailing List)

Frequently asked questions

What is CVE-2019-17558?: CVE-2019-17558 is a high-severity vulnerability in Apache Solr, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 7.5/10. Published 2019-12-30.
How severe is CVE-2019-17558?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2019-17558 known to be exploited?: Yes. CVE-2019-17558 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 103 public proof-of-concept repositories are indexed.