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TI-2026-33300 Aliases CVE-2026-45551

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

Priority MEDIUM 56CWE-639Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass, Cross-site scripting
Confidentiality · integrity · availability
None · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-639 and CWE-79.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.0023 13th percentileScored 2026-11-07
Fix Fixed groupoffice (Intermesh): 26.0.25, 25.0.1005, 6.8.165

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Intermeshgroupoffice26.0.1 to before 26.0.25; 25.0.1 to before 25.0.1005; before 6.8.16526.0.25, 25.0.1005, 6.8.165Patch availableCNA
  • groupoffice VendorIntermesh Affected 26.0.1 to before 26.0.25; 25.0.1 to before 25.0.1005; before 6.8.165 Fixed in 26.0.25, 25.0.1005, 6.8.165 Patch available CNA

Remediation

  • Fix · CNA groupoffice (Intermesh) Fixed in 26.0.25, 25.0.1005, 6.8.165

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-45551

References

Other 1

  • TI-2026-20622 Group-Office is vulnerable to RCE due to Command Injection via TNEF Attachment Handler CVSS 4.0CRITICAL 9.4
  • TI-2018-16194 Path traversal in Intermesh Group-Office lets attackers read files CVSS 4.0HIGH 8.7
  • TI-2026-20621 Group-Office is vulnerable to SSRF and File Read in WOPI service discovery CVSS 4.0HIGH 8.2
  • TI-2023-25213 Server-Side Request Forgery in groupoffice CVSS 3.1HIGH 8.8
  • TI-2025-30692 GroupOffice's Blind Stored XSS in Phone Number Field Enables Forced Redirect and Unauthorized Actions CVSS 4.0MEDIUM 6.9
  • TI-2025-18860 Group-Office has a Stored XSS Vulnerability via user's name field CVSS 4.0MEDIUM 6.9
See all 23 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences