CVE-2026-104755: Privilege Escalation (CVSS 4.8)

Description

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.

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CVSS v3.1 Score

4.8

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0031

Probability of exploitation

0.24%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-269 CWE-269

References

Other References

https://plugins.trac.wordpress.org/browser/wp-compress-image-optimizer/tags/7.10.03/addons/criticalCss/criticalCss.php#L409 https://plugins.trac.wordpress.org/browser/wp-compress-image-optimizer/tags/7.10.03/classes/ajax.class.php#L816 https://plugins.trac.wordpress.org/browser/wp-compress-image-optimizer/tags/7.10.03/classes/comms.class.php#L1042 https://plugins.trac.wordpress.org/browser/wp-compress-image-optimizer/tags/7.10.03/classes/comms.class.php#L49 https://plugins.trac.wordpress.org/browser/wp-compress-image-optimizer/tags/7.10.03/classes/users.class.php#L30 https://plugins.trac.wordpress.org/changeset?reponame=&new=3734610%40wp-compress-image-optimizer%2Ftags%2F7.26.00&old=3723132%40wp-compress-image-optimizer%2Ftags%2F7.25.00 https://www.wordfence.com/threat-intel/vulnerabilities/id/67e9bfb8-b274-422a-a50d-a6b6b24bb193?source=cve

Frequently Asked Questions

What is CVE-2026-104755? +

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. It has a CVSS v3.1 base score of 4.8 (MEDIUM).

How severe is CVE-2026-104755? +

CVE-2026-104755 has a CVSS v3.1 score of 4.8 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0031, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-104755? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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