CVE-2026-45551 MEDIUM

CVE-2026-45551: Group-Office: Authenticated Stored XSS in Administrator Context via Arbitrary Cross-User Setting Write

Vendor Intermesh
Product groupoffice
Weakness CWE-79 · XSS
Published May 29, 2026
Last update May 29, 2026

CVSS base score

5.1/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

What the vulnerability does

01Description

Group-Office is an enterprise customer relationship management and groupware tool. Prior to 26.0.25, 25.0.100, and 6.8.165, GroupOffice allows authenticated users to persist arbitrary legacy settings for any user_id via index.php?r=core/saveSetting. A separate client-side sink in the email module injects the email_font_size setting directly into JavaScript without escaping. By combining these two issues, any low-privileged authenticated user can overwrite an administrator's email_font_size setting with a JavaScript payload and trigger stored XSS in the administrator's browser when the GroupOffice web client loads views/Extjs3/modulescripts.php. This vulnerability is fixed in 26.0.25, 25.0.100, and 6.8.165.

Key dates

02Disclosure timeline

May 29, 2026 CVE published
May 29, 2026 Record updated

Related vulnerabilities

04Related CVE