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Public proof of conceptFix available

CVE-2020-8866

A public proof of concept exists; no exploitation attested.

  • Published2020-03-23
  • WeaknessCWE-434

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2020-03-11Exploit-DB entryExploit-DB

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-8866?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-8866?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Debian debian linux
BranchAffectedFixed in
8.0= 8.0no fix published
Horde groupware
BranchAffectedFixed in
5.2= 5.2.22no fix published
Horde horde form
BranchAffectedFixed in
2.0< 2.0.202.0.20

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • php-horde-formUbuntu:18.04:LTSall versions · no fixed version listed
  • php-horde-formUbuntu:16.04:LTSall versions · no fixed version listed
  • php-horde-formDebian:12all versions · fixed in 2.0.20-1
  • php-horde-formDebian:8all versions · fixed in 2.0.8-2+deb8u2

Full record on NVD

Fix

Advisories and patches

Detection

read 2026-11-03 22:42 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
EDB-48209EDB-48210
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.16.5read 2026-10-23
  • CNACVSS 3.04.3known since 2026-10-23
  • NVDCVSS 2.04read 2026-10-23
  • CNAweakness (CWE)CWE-434known since 2026-10-23
  • NVDweakness (CWE)CWE-434read 2026-10-23
  • FIRST EPSSEPSS score9.6 %2026-11-03
  • Exploit-DBdetectionread 2026-11-03
  • OSVaffected packages—

Identifiers

  • EUVD-2020-29708same flawENISA EUVD · LicenseRef-ENISA-legal-notice
  • DLA-2162-1advisory covering several CVEsDebian · LicenseRef-unstated

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Published
2020-03-23
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2020-8866?

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.

Is CVE-2020-8866 actively exploited?

Active exploitation of CVE-2020-8866 has not been confirmed. Its EPSS score was 9.6% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-8866?

CVE-2020-8866 has a CVSS v3 base score of 6.5 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N.

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