No exploitation reportedFix available

CVE-2018-1000823

Q: What is 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.

Q: Is CVE-2018-1000823 actively exploited?

Active exploitation of CVE-2018-1000823 has not been confirmed. Its EPSS score was 1.9% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2018-1000823?

CVE-2018-1000823 has a CVSS v3 base score of 10 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

No exploitation reported by the sources we read.

Published2018-12-20
Fixed in5.0.0
WeaknessCWE-611

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC

2018-12-2015:29CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2018-1000823?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2018-1000823?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Exist-db exist

Branch	Affected	Fixed in	Source
5.0	< 5.0.0	5.0.0	NVD
5.0	= 5.0.0	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Exist-db exist to 5.0.0

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.110read 2026-10-23
NVDCVSS 2.07.5read 2026-10-23
NVDweakness (CWE)CWE-611read 2026-10-23
FIRST EPSSEPSS score1.9 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Published: 2018-12-20
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is 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.

Is CVE-2018-1000823 actively exploited?

Active exploitation of CVE-2018-1000823 has not been confirmed. Its EPSS score was 1.9% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2018-1000823?

CVE-2018-1000823 has a CVSS v3 base score of 10 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

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