CVE-2026-34838
Group-Office: Authenticated Remote Code Execution via PHP Insecure Deserialization in `AbstractSettingsCollection`
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.
INFO
Published Date :
April 2, 2026, 8:16 p.m.
Last Modified :
April 15, 2026, 5:29 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-34838
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | [email protected] | ||||
| CVSS 3.1 | CRITICAL | MITRE-CVE |
Solution
- Update Group-Office to version 6.8.156 or later.
- Update Group-Office to version 25.0.90 or later.
- Update Group-Office to version 26.0.12 or later.
Public PoC/Exploit Available at Github
CVE-2026-34838 has a 2 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-34838.
| URL | Resource |
|---|---|
| https://github.com/Intermesh/groupoffice/releases/tag/v25.0.90 | Release Notes |
| https://github.com/Intermesh/groupoffice/releases/tag/v26.0.12 | Release Notes |
| https://github.com/Intermesh/groupoffice/releases/tag/v6.8.156 | Release Notes |
| https://github.com/Intermesh/groupoffice/security/advisories/GHSA-h22j-frrf-5vxq | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-34838 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-34838
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
CVE-2026-34838 PoC (Proof of Concept)
Python
📡 PoC auto collect from GitHub. ⚠️ Be careful Malware.
security cve exploit poc vulnerability
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-34838 vulnerability anywhere in the article.
-
Daily CyberSecurity
Keycloak Under Siege: Patch Now to Stop Token Theft and Account Takeovers
The popular open-source identity and access management solution Keycloak has released a critical security update, version 26.5.7, addressing a series of vulnerabilities that could allow attackers to b ... Read more
-
Daily CyberSecurity
CVE-2026-34838 (CVSS 10): Critical RCE Flaw Uncovered in GroupOffice CRM
In a significant discovery for enterprises and public sector organizations, a critical security vulnerability has been unmasked in GroupOffice, the popular open-source CRM and groupware suite. The fla ... Read more
The following table lists the changes that have been made to the
CVE-2026-34838 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Apr. 15, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:intermesh:group-office:*:*:*:*:*:*:*:* versions up to (excluding) 6.8.156 *cpe:2.3:a:intermesh:group-office:*:*:*:*:*:*:*:* versions from (including) 25.0.1 up to (excluding) 25.0.90 *cpe:2.3:a:intermesh:group-office:*:*:*:*:*:*:*:* versions from (including) 26.0.1 up to (excluding) 26.0.12 Added Reference Type GitHub, Inc.: https://github.com/Intermesh/groupoffice/releases/tag/v25.0.90 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/Intermesh/groupoffice/releases/tag/v26.0.12 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/Intermesh/groupoffice/releases/tag/v6.8.156 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/Intermesh/groupoffice/security/advisories/GHSA-h22j-frrf-5vxq Types: Vendor Advisory -
New CVE Received by [email protected]
Apr. 02, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H Added CWE CWE-502 Added Reference https://github.com/Intermesh/groupoffice/releases/tag/v25.0.90 Added Reference https://github.com/Intermesh/groupoffice/releases/tag/v26.0.12 Added Reference https://github.com/Intermesh/groupoffice/releases/tag/v6.8.156 Added Reference https://github.com/Intermesh/groupoffice/security/advisories/GHSA-h22j-frrf-5vxq