Medium severity · published May 29, 2026
CVE-2026-45551
Group-Office: Authenticated Stored XSS in Administrator Context via Arbitrary Cross-User Setting Write
5.1
CVSS
0.2%
EPSS
No
On KEV
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.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 14% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
GR
groupoffice · Intermesh
>= 26.0.1, < 26.0.25; >= 25.0.1, < 25.0.1005; < 6.8.165 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-45551
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-45551
github.com
https://github.com/Intermesh/groupoffice/security/advisories/GHSA-9w92-p32g-g99p
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