Vulnerability · Published May 29, 2026 · Assigned by GitHub_M

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

Medium 5.1

In plain English

A medium-severity cross-site scripting in groupoffice from Intermesh. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 14% of all known vulnerabilities).

Severity (CVSS 4.0)5.1Medium

Exploit odds (30 days)0.2%top 86.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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 (as reported)

Vendor	Product	Versions
Intermesh	groupoffice	>= 26.0.1, < 26.0.25>= 25.0.1, < 25.0.1005< 6.8.165

Weakness: CWE-79, CWE-639 · 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

References

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