PatchSiren cyber security CVE debrief
CVE-2016-6897 Wordpress CVE debrief
CVE-2016-6897 is a WordPress core cross-site request forgery (CSRF) issue in the wp_ajax_update_plugin handler. According to the CVE record, the bug could let a remote attacker abuse an authenticated browser session because the nonce check was performed too late in the request flow. NVD rates the issue at CVSS 6.5 (medium) and maps it to CWE-352. WordPress versions before 4.6 are listed as affected.
- Vendor
- Wordpress
- Product
- CVE-2016-6897
- CVSS
- MEDIUM 6.5
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2017-01-18
- Original CVE updated
- 2026-05-13
- Advisory published
- 2017-01-18
- Advisory updated
- 2026-05-13
Who should care
Organizations running WordPress before 4.6, especially teams that allow subscriber accounts or rely on wp-admin AJAX workflows for plugin updates. Site operators should treat this as a core authentication/session integrity issue affecting logged-in users.
Technical summary
The vulnerability is a CSRF flaw in wp-admin/includes/ajax-actions.php, specifically the wp_ajax_update_plugin function. The CVE description says the check_ajax_referer validation occurred late, which could allow a crafted request to reach sensitive plugin-update logic using a victim subscriber's authenticated session. NVD lists affected WordPress versions through 4.5.5 and classifies the weakness as CWE-352.
Defensive priority
Medium; upgrade WordPress instances before 4.6 as soon as practical and treat public-facing sites as higher risk.
Recommended defensive actions
- Upgrade WordPress core to a version newer than 4.6 on all affected sites.
- Verify no production system is still running a version covered by the NVD vulnerable range through 4.5.5.
- Review any custom admin or automation workflows that depend on wp_ajax_update_plugin or similar wp-admin AJAX endpoints.
- Limit unnecessary subscriber accounts and remove stale authenticated sessions where possible.
- Monitor for unexpected plugin update activity originating from authenticated browser sessions.
Evidence notes
The CVE description explicitly identifies a CSRF flaw in wp_ajax_update_plugin in wp-admin/includes/ajax-actions.php and says the issue is related to CVE-2016-6896. NVD assigns CVSS 6.5/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N, maps the weakness to CWE-352, and lists WordPress versions through 4.5.5 as vulnerable. The CVE metadata also includes a WordPress GitHub commit reference and multiple advisory/discussion references as supporting material.
Official resources
The CVE record was published on 2017-01-18. The supplied metadata also points to an oss-security reference dated 2016-08-20, indicating earlier public discussion in the upstream reference trail.