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CVE-2026-34838

9.9 · CRITICAL

Group-Office is an enterprise customer relationship management and groupware tool.

Published Apr 2, 2026CWE-502EPSS 0.99%

Overview

CVE-2026-34838 is a critical-severity vulnerability. It was published on April 2, 2026 and has a CVSS 3.1 base score of 9.9 (CRITICAL).

This vulnerability has a CVSS 3.1 base score of 9.9, rated CRITICAL. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

Technical 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

GitHubgithub.com/Intermesh/groupoffice/releases/tag/v25.0.90GitHubgithub.com/Intermesh/groupoffice/releases/tag/v26.0.12GitHubgithub.com/Intermesh/groupoffice/releases/tag/v6.8.156GitHubgithub.com/Intermesh/groupoffice/security/advisories/GHSA-h22j-frrf-5vxq

How CyberStrike helps

Frequently asked questions

What is CVE-2026-34838?

CVE-2026-34838 is a critical-severity vulnerability. It was published on April 2, 2026 and has a CVSS 3.1 base score of 9.9 (CRITICAL).

How severe is CVE-2026-34838?

This vulnerability has a CVSS 3.1 base score of 9.9, rated CRITICAL. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2026-34838?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-34838?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-34838 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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