WordPress Core < 5.0 — Denial of Service
CVE-2018-6389Published · Updated Action summary
Affected: <5.0Update to 5.0 or newer
All remediation steps- Severity
- High7.5
- CVSS
- 7.5CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HWhat does this vector mean?
AV:NAttack vector- Network
AC:LAttack complexity- Low
PR:NPrivileges required- None
UI:NUser interaction- None
S:UScope- Unchanged
C:NConfidentiality- None
I:NIntegrity- None
A:HAvailability- High
- Required access
- No account needed
- Exploit prediction (EPSS)
- No score
- CISA KEV
- Not listed
On this page7
Am I affected?
WordPress wordpress
- Affected< 5.0
- Patched in5.0
Update to 5.0 or newer.
You are affected if you run < 5.0. Version 5.0 and later are not affected by this issue.
- Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under WordPress.
- No admin access? Run a passive check of your site. It reads public files only.
- No account is needed to exploit this. Treat any exposed site on an affected version as at risk.
What to do
- Update to version 5.0, or a newer patched version
- Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
- Watch WordPress to get an email when the next vulnerability is published.
Advisory
Source description from Wordfence Intelligence, credited to Barak Tawily.
In WordPress before 5.0, unauthenticated attackers can cause a denial of service (resource consumption) by using the large list of registered .js files (from wp-includes/script-loader.php) to construct a series of requests to load every file many times. It looks like most of the slowness was due to forcing PHP to repeatedly compress the output scripts, which was addressed in 5.0.
Exploits & references
Proof-of-concept & detection
No public proof-of-concept or detection template is known for this vulnerability.
Advisories & patches
- Advisorywordfence.com
Timeline
CVE published
Severity high, CVSS 7.5
Record last updated
Sources & licenses
Wordfence record- Vulnerability data
- Wordfence Intelligence. Copyright 2012-2026 Defiant Inc. Licensed under the CC BY-SA 4.0.
- CVE® identifiers
- Copyright 1999-2026 The MITRE Corporation. Used under the CVE Program. CVE® is a registered trademark of The MITRE Corporation.
- CVSS / CWE
- National Vulnerability Database (NVD), shown unmodified. This product uses the NVD API but is not endorsed or certified by the NVD.
- VulnCrest content
- Summary, remediation guidance and page layout © VulnCrest. Not sourced from NVD.