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WordPress Core - Cross-Site Request Forgery (CSRF) (CVE-2016-6635)

CVE-2016-6635

Cross-site request forgery (CSRF) vulnerability in the wp_ajax_wp_compression_test function in wp-admin/includes/ajax-actions.php in WordPress before 4.5 allows remote attackers to hijack the authentication of administrators for requests that change the script compression option.

CVE-2016-6635

HIGH CVSS 8.8 Published 2016-08-07 Updated 2026-06-17
AI Risk Critical (100/100) Active Exploit: Likely Published Exploit: Public exploit references found Priority: P1 Immediate
Severity Band HIGH
CVSS Vector CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Affected Components 1
Reference Links 4
AI Risk Engine Critical (100/100)
Exploitability High
Active Exploitation Likely
Published Exploit Status Public exploit references found

Threat Timeline

  1. 2016-08-07 CVE published and first recorded in the threat feed.
  2. 2026-06-17 Record updated with latest vulnerability metadata.
  3. 2026-09-18 AI technical context refreshed for mitigation and impact guidance.
  4. Now Monitoring for follow-up changes, linked references, and new related CVEs.

AI Context

Machine-generated threat intelligence

AI Updated just now

AI enriched just now (2026-09-18 20:10 UTC)

Technical Summary

Cross-site request forgery (CSRF) vulnerability in the wp_ajax_wp_compression_test function in wp-admin/includes/ajax-actions.php in WordPress before 4.5 allows remote attackers to hijack the authentication of administrators for requests that change the script compression option.

Potential Impact

Severity is HIGH (CVSS 8.8). Depending on deployment context, affected components may be exposed to unauthorized actions or data integrity risk.

Exploitability Assessment

Exploitability is assessed as High based on published exploit references.

Primary risk drivers: published exploit references

Mitigation Recommendations

Validate affected product versions, prioritize patching, and monitor references for vendor remediation guidance. If immediate patching is not possible, apply compensating controls and limit exposure of vulnerable surfaces.

Detection & Monitoring

Track authentication anomalies, unexpected file writes, and suspicious plugin API activity around affected components.

Business Impact Lens

AI risk score 100/100 (Critical, High) with priority P1 Immediate. Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.

Affected Products

WordPress Core CORE · wordpress Affected: <= 4.4.2 Fixed in: 4.5

References

What to do about this

Patch on your next cycle Worth fixing, but not ahead of other work.

Fix it

Update WordPress Core to 4.5 or later.

That is the complete fix. Everything below is what protects you in the meantime.

Cannot update today? Request / payload inspection (WAF) in Hack Halt ProSecure blocks this class of attack before WordPress processes the request.

Inspect request parameters and bodies for injection, traversal and file-inclusion payloads, and refuse the request rather than logging it.

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Not sure if you are affected?

Scan your site to see whether it runs WordPress Core, and at which version.

Free, no installation, no account. It reads what your site already publishes, then tells you which plugins carry known vulnerabilities and what to do about each one.

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Am I affected by this vulnerability?

You are affected if your site runs WordPress Core. Versions below 4.5 are vulnerable; that release and later are not.

How do I fix it?

Update WordPress Core to version 4.5 or later. That is the complete fix. Until you can update, Request / payload inspection (WAF) in Hack Halt ProSecure contains this class of attack at the request layer.

What can an attacker actually do?

This is a Cross-Site Request Forgery (CSRF) flaw. An attacker who exploits it can make a logged-in administrator perform an action just by visiting a page.