CVE-2026-45551

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

MEDIUM
5.1
CVSS Score
Published: May 29, 2026 at 12:34 PM UTC
Updated: July 21, 2026 at 01:39 PM UTC
1 product affected across 1 vendorGroup-Office

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Severity
MEDIUM5.1
Exploit prediction
EPSS 0.2%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 25.0.1005v < 26.0.25v < 6.8.165
Affected range stops below 25.0.1005, so it looks safe — our inference, not a vendor statement
Affected range stops below 26.0.25, so it looks safe — our inference, not a vendor statement
Affected range stops below 6.8.165, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.1MEDIUMGitHub_M
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-79CWE-639

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