CVE-2018-1000823: exist version <= 5.0.0-RC4 contains a XML External Entity (XXE) vulnerability in XML Parser for REST Server th

Q: How do I fix CVE-2018-1000823?

exist: upgrade to 5.0.0. Exact commands for each OS are on this page.

Q: Is CVE-2018-1000823 being exploited?

CVE-2018-1000823 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2018-1000823 affect?

CVE-2018-1000823 affects exist. Severity is critical (CVSS 10.0). 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: How urgent is CVE-2018-1000823?

Priority 60/100. Critical severity; Remotely exploitable, no login, no user action

This week

CRITICAL 10.0REMOTEUPGRADE

CVE-2018-1000823 is a critical-severity flaw (CVSS 10.0) affecting exist. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	10.0 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.9% (top 21%)
CISA exploited list	No
Weakness	CWE-611
Published	2018-12-20
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: exist-db

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2018-12-20 15:29 UTCPublished CVE record published
2026-06-17 01:33 UTCUpdated Record last modified

exist-db exist UPGRADE

Affected: < 5.0.0 · 5.0.0 rc1 · 5.0.0 rc2 · 5.0.0 rc3 · 5.0.0 rc4

Fixed in: 5.0.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy exist || rpm -q exist || exist --version

2. UPGRADE to 5.0.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade exist

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade exist

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2018-1000823?

exist: upgrade to 5.0.0. Exact commands for each OS are on this page.

Is CVE-2018-1000823 being exploited?

CVE-2018-1000823 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2018-1000823 affect?

CVE-2018-1000823 affects exist. Severity is critical (CVSS 10.0). 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.

How urgent is CVE-2018-1000823?

Priority 60/100. Critical severity; Remotely exploitable, no login, no user action

References

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