What is CVE-2020-27387?

CVE-2020-27387 is a high-severity vulnerability in Horizontcms Project, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 8.8/10. Published 2020-11-05.

How severe is CVE-2020-27387?

High severity. CVSS v3 base score is 8.8 out of 10.

Is CVE-2020-27387 known to be exploited?

3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Arbitrary file upload in Horizontcms Project

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.

Vulnerability class: Unrestricted File Upload

Published 2020-11-05 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.185 (97.2th percentile), scored 2026-10-01.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 97th percentile — 97.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.185 · newest: 0.185 · change: 0.000

Affected products

Horizontcms Project — versions 1.0.0

Weakness classification (CWE)

CWE-434 — Unrestricted Upload of File with Dangerous Type

Public proof-of-concept exploits

References

github.com/rapid7/metasploit-framework/pull/14340 (Third Party Advisory)
github.com/ttimot24/HorizontCMS/commit/436b5ab679fd27afa3d99c023dbe103113da4fee (Patch, Third Party Advisory)
blog.vonahi.io/whats-in-a-re-name/ (Exploit, Patch, Third Party Advisory)
packetstormsecurity.com/files/160046/HorizontCMS-1.0.0-beta-Shell-Upload.html (Exploit, VDB Entry, Third Party Advisory)

Frequently asked questions

What is CVE-2020-27387?: CVE-2020-27387 is a high-severity vulnerability in Horizontcms Project, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 8.8/10. Published 2020-11-05.
How severe is CVE-2020-27387?: High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2020-27387 known to be exploited?: 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.