What is CVE-2018-1000823?

CVE-2018-1000823 is a critical-severity vulnerability in Exist-Db Exist, classified under Improper Restriction of XML External Entity Reference (XXE). CVSS score: 10.0/10. Published 2018-12-20.

How severe is CVE-2018-1000823?

Critical severity. CVSS v3 base score is 10.0 out of 10.

XXE in Exist-Db Exist

CVE-2018-1000823

exist version <= 5.0.0-RC4 contains a XML External Entity (XXE) vulnerability in XML Parser for REST Server that can result in Disclosure of confidential data, denial of service, SSRF, port scanning.

Vulnerability class: XXE (XML External Entity)

Published 2018-12-20 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.019 (78.6th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 79th percentile — 78.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.019 · newest: 0.019 · change: 0.000

Affected products

Exist-Db Exist — versions 5.0.0

Weakness classification (CWE)

CWE-611 — Improper Restriction of XML External Entity Reference (XXE)

References

0dd.zone/2018/10/27/exist-XXE/ (Third Party Advisory)
github.com/eXist-db/exist/issues/2180 (Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2018-1000823?: CVE-2018-1000823 is a critical-severity vulnerability in Exist-Db Exist, classified under Improper Restriction of XML External Entity Reference (XXE). CVSS score: 10.0/10. Published 2018-12-20.
How severe is CVE-2018-1000823?: Critical severity. CVSS v3 base score is 10.0 out of 10.