CVE-2026-104755: WP Compress privilege escalation vulnerability
medium 4.8 published 2026-10-16
- Affected versions
- 7.25.00 and older
- Fixed in
- 7.26.00 *
- Latest version
- 7.30.45
- Severity
- Medium · CVSS 4.8
- Active installs
- 9,000+
- Type
- Privilege escalation
* The source does not name a fixed version; this is the first wordpress.org release after the last affected version.
What an attacker needs
- Access: None. No account or login is needed.
CVSS vector (score by Wordfence): CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
What to do now
- Update WP Compress to 7.26.00 or newer (the latest is 7.30.45): Dashboard → Updates, or Plugins → “update now”.
- If you cannot update right away, deactivate it until you can.
- Turn on auto-updates for it: Plugins → “Enable auto-updates” on its row.
- Not sure which version you run? Check your version against every known WP Compress issue.
With WP-CLI:
wp plugin get wp-compress-image-optimizer --field=version. - If you ran an affected version and something looks off (new admin users, spam pages, redirects), run the free scan below.
The advisory
The WP Compress – Instant Performance & Speed Optimization plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 7.25.00 The vulnerability exists because the `start_comms` dispatcher (`wps_ic_comms::start_comms`), hooked on every front-end request, gates access only by comparing the caller-supplied `apikey` parameter against the stored plugin API key with no WordPress capability check and no nonce verification, then passes the unvalidated `group`, `setting`, and `value` parameters directly to `change_setting()`, which writes them into the `WPS_IC_SETTINGS` option without an allow-list. This makes it possible for unauthenticated attackers to write arbitrary permission keys into the plugin's settings, causing `wps_ic_users::checkAndAddCaps()` to grant any WordPress role — including Subscriber — the `manage_wpc_settings` capability and thereby achieve plugin-administrator-equivalent control over the plugin's optimization, CDN, and critical-CSS surfaces. The API key required to pass the authorization check can itself be obtained without authentication via the `wpc_send_critical_remote` nopriv AJAX action: when the external critical-CSS service returns an `apiResults` field, `initCritical()` echoes the stored plugin API key back to the caller in a `wp_send_json_success` response, completing the exploit chain entirely without a WordPress login.
References
- NVD CVE-2026-104755 nvd.nist.gov
- Wordfence advisory www.wordfence.com
- Code change (fix) plugins.trac.wordpress.org
- Plugin source plugins.trac.wordpress.org
Related
Ran an affected version? Check your site for signs of a hack
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Where this data comes from
- CVE record, score and references: NIST National Vulnerability Database (NVD), checked 2026-11-04. This product uses data from the NVD API but is not endorsed or certified by the NVD.
- Versions and install counts: wordpress.org/plugins/wp-compress-image-optimizer (Plugins API), fetched 2026-11-04.
- The summary, “what an attacker needs” and “what to do” sections are our plain-English reading of the record and the plugin's release history; the quoted description is the record's own text. Spot an error? Email Daniel.