CVE-2026-34838

Name: CVE-2026-34838
Creator: NVD / NIST
Published: 2026-04-02T20:16:28.15+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.9/10EPSS 1.03%

Last modified Jun 17, 2026

CVE-2026-34838 is a critical-severity vulnerability rated 9.9/10 on the CVSS scale. Group-Office is an enterprise customer relationship management and groupware tool. Prior to versions 6.8.156, 25.0.90, and 26.0.12, a vulnerability in the AbstractSettingsCollection model leads to insecure deserialization when these settings are loaded. EPSS estimates a 1.03% chance of exploitation in the next 30 days.

Description

Group-Office is an enterprise customer relationship management and groupware tool. Prior to versions 6.8.156, 25.0.90, and 26.0.12, a vulnerability in the AbstractSettingsCollection model leads to insecure deserialization when these settings are loaded. By injecting a serialized FileCookieJar object into a setting string, an authenticated attacker can achieve Arbitrary File Write, leading directly to Remote Code Execution (RCE) on the server. This issue has been patched in versions 6.8.156, 25.0.90, and 26.0.12.

Metrics

CVSS 3.1

9.9/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS Probability

1.03%

59.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-502

Affected Software

Vendor	Product	Versions
Intermesh	Group-Office	< 6.8.156
Intermesh	Group-Office	>= 25.0.1, < 25.0.90
Intermesh	Group-Office	>= 26.0.1, < 26.0.12

References

https://github.com/Intermesh/groupoffice/releases/tag/v25.0.90Release Notes
https://github.com/Intermesh/groupoffice/releases/tag/v26.0.12Release Notes
https://github.com/Intermesh/groupoffice/releases/tag/v6.8.156Release Notes
https://github.com/Intermesh/groupoffice/security/advisories/GHSA-h22j-frrf-5vxqVendor Advisory

Timeline

Published: Apr 2, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-34838?

How severe is CVE-2026-34838?

CVE-2026-34838 has a CVSS score of 9.9/10 (CRITICAL severity). The EPSS model estimates a 1.03% probability of exploitation in the next 30 days.

How do I fix CVE-2026-34838?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-34838?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST