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Debian LinuxOperating system · Debian

CVE-2020-8866

MEDIUM · 6.5 CVSS v3.1 Published 2020-03-23
Fix available
A fix is available. Upgrade to 2.0.20 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
This vulnerability allows remote attackers to create arbitrary files on affected installations of Horde Groupware Webmail Edition 5.2.22. Authentication is required to exploit this vulnerability. The specific flaw exists within add.php. The issue results from the lack of proper validation of user-supplied data, which can allow the upload of arbitrary files. An attacker can leverage this in conjunction with other vulnerabilities to execute code in the context of the www-data user. Was ZDI-CAN-10125.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Authenticated remote attackers can upload arbitrary files to Horde Groupware Webmail Edition 5.2.22 via the add.php component due to insufficient validation of user-supplied data. This file upload vulnerability can be chained with other vulnerabilities to achieve code execution as the www-data user.

MitigationImplement proper file type and content validation in add.php, restrict allowed file extensions, and update to a patched version of Horde Groupware if available.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Debian LinuxOperating system
Affected:= 8.0
GroupwareApplication
Affected:= 5.2.22
Horde FormApplication
Affected:< 2.0.20

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Horde Groupware version
    Locate the Horde installation directory and check the version file (typically in lib/Bundle.php or similar version file within the Horde package). Run: grep -r 'version' /path/to/horde/lib | head -20
    Affected if The installed version is exactly 5.2.22
  2. Check Horde Form library version
    Examine the Horde/Form/package.xml or the version file within the Horde Form library directory. Run: find /path/to/horde -name 'Form' -type d -exec grep -l 'version' {}/package.xml \; 2>/dev/null
    Affected if The Horde Form library version is less than 2.0.20
  3. Verify add.php upload component exists
    Locate the add.php file in the Horde installation, typically under the activesync or groups module directory. Run: find /path/to/horde -name 'add.php' 2>/dev/null
    Affected if The add.php file is present and accessible via the web server
  4. Confirm file upload functionality is enabled
    Inspect the Horde configuration for file upload settings, typically in conf.php or through the Horde administration panel. Check for active upload-related configuration keys.
    Affected if File uploads are enabled in the Horde configuration and the add.php endpoint accepts file parameters
  5. Determine underlying OS version
    Run: cat /etc/debian_version or lsb_release -a
    Affected if The system is running Debian Linux version 8.0

The environment is affected if Horde Groupware version 5.2.22 or Horde Form below 2.0.20 is installed, the add.php upload component exists, and file upload functionality is enabled on a Debian 8.0 system.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to 2.0.20 or later
Fixed in 2.0.20
Interim mitigation

Implement proper file type and content validation in add.php, restrict allowed file extensions, and update to a patched version of Horde Groupware if available.

Fix this in Debian Linux Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-8866 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data