# CVE-2026-45551: Intermesh Group-Office stored XSS and privilege escalation via cross-user setting write

Source: https://junglewise.ai/threats/cve-2026-45551-intermesh-group-office-stored-xss-and-privilege-escalation-via  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-29. Updated: 2026-05-29  
License: CC BY 4.0 with a link back

CVE-2026-45551 · Severity: info · CVSS 5.1 · Published 2026-05-29

Intermesh Group-Office is an enterprise CRM and groupware suite used for managing business communications and customer data. A security flaw allows a standard user to modify the settings of other users, including administrators. By changing an administrator's email font settings to include malicious code, an attacker can take over the administrator's account when they log in, potentially leading to full system compromise and unauthorized access to sensitive company data.

Technologies: [Intermesh Group-Office](https://junglewise.ai/threats/technologies/group-office). Vendors: [Intermesh](https://junglewise.ai/threats/vendors/intermesh).

## Quick answers

**Is CVE-2026-45551 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-45551 being exploited in the wild.

**How severe is CVE-2026-45551?** Informational severity, with a CVSS score of 5.1, published 29 May 2026.

**Which products and versions are affected?** Intermesh Group-Office < 26.0.25, < 25.0.100, < 6.8.165.

**Is there a fix for CVE-2026-45551?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-45551 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-45551?** Check whether you run Intermesh Group-Office at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A vulnerability exists in Group-Office due to an authorization bypass in the 'core/saveSetting' controller (CWE-639), which fails to verify if the authenticated user has permission to modify the 'user_id' parameter. An attacker can use this to overwrite the 'email_font_size' setting for an administrator. A secondary vulnerability (CWE-79) in the email module's 'scripts.inc.php' fails to escape this setting before injecting it into a JavaScript string literal in 'modulescripts.php'. By chaining these, a low-privileged user can inject a malicious payload that executes in the administrator's browser context, leading to session hijacking and full privilege escalation. The issue is fixed in versions 26.0.25, 25.0.100, and 6.8.165.

## Affected products

- Intermesh Group-Office < 26.0.25, < 25.0.100, < 6.8.165

## Timeline

- 2026-04-14: other: Vulnerability validated by researcher
- 2026-05-11: advisory: Vendor advisory published via GitHub
- 2026-05-29: disclosed: CVE published to NVD

## References

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

## Related threats

- [Group-Office server-side request forgery in Bookmark description](https://junglewise.ai/threats/cve-2026-63653-group-office-is-an-enterprise-customer-relationship-management)
- [Group-Office template injection in Contact/labels JMAP endpoint](https://junglewise.ai/threats/cve-2026-63011-group-office-is-an-enterprise-customer-relationship-management)
- [Group-Office stored XSS in reminders via HTML/JavaScript injection](https://junglewise.ai/threats/cve-2026-63010-group-office-is-an-enterprise-customer-relationship-management)
- [Group-Office arbitrary local file read in FolderController](https://junglewise.ai/threats/cve-2026-125390-group-office-before-6-8-181-25-0-116-and-26-0-58-contains-an)
- [Intermesh Group-Office stored XSS in email viewer](https://junglewise.ai/threats/cve-2026-125389-intermesh-group-office-before-6-8-181-25-0-116-and-26-0-58)