What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 5.1 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-29 · updated 2026-07-21
• Weakness: CWE-79

Description

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.

Affected products

• Intermesh groupoffice: from 26.0.1, < 26.0.25; from 25.0.1, < 25.0.1005; before 6.8.165

References

• https://github.com/Intermesh/groupoffice/security/advisories/GHSA-9w92-p32g-g99p
• https://github.com/Intermesh/groupoffice/security/advisories/GHSA-9w92-p32g-g99p

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