CVE-2026-17153: AI Agent by SiteGround <= 1.2.7 - Missing Authorization to Authenticated (Contributor+) Arbitrary Media Upload via /generate-content REST Endpoint
The AI Agent by SiteGround plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 1.2.7. This is due to the plugin not properly verifying that a user is authorized to perform an action. This makes it possible for unauthenticated attackers to upload images to the WordPress media library, bypassing the uploadfiles capability restriction that Contributors are normally subject to, as authenticated attackers with Contributor-level access or above can satisfy the endpoint's nonce and permission checks. The sgaistudiogutenbergnonce required by the endpoint is emitted to any user with block editor access — including Contributors — making the absent uploadfiles check the sole barrier to exploitation.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
WordPress plugin: AI Agent by SiteGroundto a version that resolves this vulnerability.Fixed in 1.2.7 - Compensating control
Temporarily restrict access to the WordPress block editor (and the /generate-content REST endpoint paths that rely on sg_ai_studio_gutenberg_nonce) so that Contributor or higher users cannot be abused to obtain the nonce, until the plugin is updated.
Event History
Frequently Asked Questions
Who can exploit this issue in practice?
An attacker needs an authenticated WordPress account with Contributor-level access or higher and access to the block editor. Contributors can obtain the required sg_ai_studio_gutenberg_nonce because it is emitted to users with block editor access.
Are unauthenticated visitors able to upload media through the affected endpoint?
No. Although the authorization bypass concerns the upload_files capability restriction, the endpoint still requires a nonce and permission checks that authenticated Contributor-level users or above can satisfy.
What is the security impact for affected sites?
A Contributor or higher-privileged user can upload images to the WordPress media library through the /generate-content REST endpoint despite normally lacking the upload_files capability. The provided severity vector indicates integrity impact only, with no stated confidentiality or availability impact.
How can I determine whether my site is affected?
The issue affects AI Agent by SiteGround versions up to and including 1.2.7. Sites using an affected version and allowing Contributor-level accounts block editor access are exposed to this capability bypass.