Auth bypass in Siteground Ai Agent By

CVE-2026-17153

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 upload_files 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 sg_ai_studio_gutenberg_nonce required by the endpoint is emitted to any user with block editor access — including Contributors — making the absent upload_files check the sole barrier to exploitation.

Vulnerability class: Broken Access Control

Published · last modified .

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.005 (37.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 38th percentile — 37.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-17153: held from 0.003 to 0.005.

EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-17153?
CVE-2026-17153 is a medium-severity vulnerability in Siteground Ai Agent By, classified under Missing Authorization. CVSS score: 5.3/10. Published 2026-08-20.
How severe is CVE-2026-17153?
Medium severity. CVSS v3 base score is 5.3 out of 10.