CVE-2026-27947Public exploitNetwork attack vector

Authenticated command execution via zip option injection

Published Feb 27, 2026 · Updated Feb 27, 2026

Argument injection in GroupOffice before 26.0.9, 25.0.87, and 6.8.154 allows remote authenticated users to execute commands. MessageController extracts attacker-named files from a TNEF attachment, then passes a shell-expanded wildcard to zip, which interprets leading-hyphen filenames as options. A valid session and security token can reach the handler, and successful exploitation runs commands as the web server user.

CVSS severity9.4
Critical
EPSS probability0.73%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Argument injection in GroupOffice before 26.0.9, 25.0.87, and 6.8.154 allows remote authenticated users to execute commands. MessageController extracts attacker-named files from a TNEF attachment, then passes a shell-expanded wildcard to zip, which interprets leading-hyphen filenames as options. A valid session and security token can reach the handler, and successful exploitation runs commands as the web server user.

The record

CVE
CVE-2026-27947
Published
Feb 27, 2026
Updated
Feb 27, 2026
Vendor
Intermesh BV
Product
GroupOffice
Classifications
CWE-88, CWE-434, T1059.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 27, 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=>= 25.0.0, < 25.0.87
  2. Affected versionversion=>= 26.0.0, < 26.0.9
  3. Affected versionversion=< 6.8.154

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Intermesh BV · GroupOfficeversion=>= 25.0.0, < 25.0.87; version=>= 26.0.0, < 26.0.9; version=< 6.8.154

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
9.4GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

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-88Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
CWE-434Unrestricted Upload of File with Dangerous Type
T1059.004Unix Shell

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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