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Exploitation reportedNot in CISA KEV yetFix available

CVE-2020-27387

Exploitation reported by one source. First attested on 2025-07-13 by GCVE · shadowserver.

  • Published2020-11-05
  • WeaknessCWE-434

Am I affected?

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Description

An unrestricted file upload issue in HorizontCMS through 1.0.0-beta allows an authenticated remote attacker (with access to the FileManager) to upload and execute arbitrary PHP code by uploading a PHP payload, and then using the FileManager's rename function to provide the payload (which will receive a random name on the server) with the PHP extension, and finally executing the PHP file via an HTTP GET request to /storage/<php_file_name>. NOTE: the vendor has patched this while leaving the version number at 1.0.0-beta.

Timeline

dates in UTC
  1. 2020-11-0502:15CVE publishedNVD
  2. 2025-07-1311:29Listed as exploited by GCVEGCVE
  3. 2025-07-1311:29Exploitation first reportedGCVE

Observed activity

isMalicious corpus · updated 2026-11-04 09:37 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-2020-27387?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-27387?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Horizontcms project horizontcms
BranchAffectedFixed in
1.0= 1.0.0no fix published

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

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
1 moduleexploit/multi/http/horizontcms_upload_execrank: excellentModule metadata: Metasploit Framework, © Rapid7, Inc., BSD-3-Clause.
Metasploit Framework

Sources

  • GCVEexploitation2025-07-13
  • NVDCVSS 3.18.8read 2026-10-23
  • NVDCVSS 2.06.5read 2026-10-23
  • NVDweakness (CWE)CWE-434read 2026-10-23
  • FIRST EPSSEPSS score18.5 %read 2026-11-03
  • Metasploit FrameworkMetasploit modules1known since 2026-11-01

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2020-11-05
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2020-27387?

An unrestricted file upload issue in HorizontCMS through 1.0.0-beta allows an authenticated remote attacker (with access to the FileManager) to upload and execute arbitrary PHP code by uploading a PHP payload, and then using the FileManager's rename function to provide the payload (which will receive a random name on the server) with the PHP extension, and finally executing the PHP file via an HTTP GET request to /storage/<php_file_name>. NOTE: the vendor has patched this while leaving the version number at 1.0.0-beta.

Is CVE-2020-27387 actively exploited?

Active exploitation of CVE-2020-27387 has not been confirmed. Its EPSS score was 18.5% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-27387?

CVE-2020-27387 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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