CVE-2026-45551Public exploitNetwork attack vector

Administrator takeover via cross-user setting injection

Published May 29, 2026 · Updated May 29, 2026

Stored XSS in GroupOffice before 26.0.25, 25.0.100, and 6.8.165 allows remote authenticated users to run JavaScript as an administrator. The core/saveSetting controller accepts any user_id without authorization, while email_font_size is inserted unescaped into JavaScript by the email bootstrap. A low-privileged account can poison an administrator's setting; execution occurs when that administrator loads the web client, exposing administrator-accessible data and actions.

CVSS severity5.1
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in GroupOffice before 26.0.25, 25.0.100, and 6.8.165 allows remote authenticated users to run JavaScript as an administrator. The core/saveSetting controller accepts any user_id without authorization, while email_font_size is inserted unescaped into JavaScript by the email bootstrap. A low-privileged account can poison an administrator's setting; execution occurs when that administrator loads the web client, exposing administrator-accessible data and actions.

The record

CVE
CVE-2026-45551
Published
May 29, 2026
Updated
May 29, 2026
Vendor
Intermesh BV
Product
GroupOffice
Classifications
CWE-79, CWE-639, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 29, 2026CVE publishedPublication date reported by the CVE source.
  2. May 29, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 25.0.1, < 25.0.1005
  2. Affected versionversion=>= 26.0.1, < 26.0.25
  3. Affected versionversion=< 6.8.165

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Intermesh BV · GroupOfficeversion=>= 25.0.1, < 25.0.1005; version=>= 26.0.1, < 26.0.25; version=< 6.8.165

Published CVSS scores

5.1GitHub, Inc.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

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-639Authorization Bypass Through User-Controlled Key
T1059.007Command and Scripting Interpreter: JavaScript/JScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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