WordPress plugin
Captcha 4.3.6 — 4.4.4 - Plugin Backdoor
cacd31bd-ccc6-49fa-89f1-09f3c5cd9072Published · Updated Action summary
Affected: 4.3.6 – 4.4.4Update to 4.4.5 or newer
All remediation steps- Severity
- Critical9.6
- CVSS
- 9.6CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:HWhat does this vector mean?
AV:NAttack vector- Network
AC:LAttack complexity- Low
PR:NPrivileges required- None
UI:RUser interaction- Required
S:CScope- Changed
C:HConfidentiality- High
I:HIntegrity- High
A:HAvailability- High
- Weakness
- CWE-912 Hidden Functionality
- Required access
- No account needed
- Exploit prediction (EPSS)
- No score
- CISA KEV
- Not listed
On this page8
Am I affected?
Captcha captcha
- Affected4.3.6 – 4.4.4
- Patched in4.4.5
Update to 4.4.5 or newer.
You are affected if you run 4.3.6 – 4.4.4. Version 4.4.5 and later are not affected by this issue.
- Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Captcha.
- 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 4.4.5, or a newer patched version
- Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
- Watch Captcha to get an email when the next vulnerability is published.
Advisory
Source description from Wordfence Intelligence, credited to Matt Barry.
The Captcha plugin for WordPress contained a backdoor that injected SEO spam into unsuspecting users WordPress sites in version 4.3.6 to 4.4.4.
Exploits & references
Proof-of-concept & detection
No public proof-of-concept or detection template is known for this vulnerability.
Advisories & patches
- Advisorywordfence.com
Related CVEs
More in Captcha
All 3| Severity | Vulnerability | CVE | Published |
|---|---|---|---|
| Medium6.1 | Reflected Cross-Site Scripting <4.3.0Update to 4.3.0 | — | |
| Medium5.3 | Captcha Bypass ≤3.8.1Update to 3.8.2 | — |
- Medium6.1Reflected Cross-Site Scripting
<4.3.0Update to 4.3.0
- Medium5.3Captcha Bypass
≤3.8.1Update to 3.8.2
Timeline
CVE published
Severity critical, CVSS 9.6
Record last updated
Sources & licenses
- Vulnerability data
- Wordfence Intelligence. Copyright 2012-2026 Defiant Inc. Licensed under the CC BY-SA 4.0.
- 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.