Cyber Posture

CVE-2023-53921

CriticalPublic PoC

Published: 17 December 2025

Published
17 December 2025
Modified
31 December 2025
KEV Added
Patch
CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0057 68.7th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Description

SitemagicCMS 4.4.3 contains a remote code execution vulnerability that allows attackers to upload malicious PHP files to the files/images directory. Attackers can upload a .phar file with system command execution payload to compromise the web application and execute arbitrary system…

more

commands.

Mitigating Controls (NIST 800-53 r5)AI

prevent

Directly remediates the specific unrestricted file upload flaw in SitemagicCMS by applying vendor-provided patches to prevent malicious .phar uploads.

prevent

Validates file uploads to block dangerous types like .phar containing PHP code execution payloads, addressing the core CWE-434 vulnerability.

prevent

Enforces secure configuration settings on the web server to disable script execution in the files/images directory, preventing RCE even if malicious files are uploaded.

Security SummaryAI

SitemagicCMS version 4.4.3 is affected by CVE-2023-53921, a remote code execution vulnerability stemming from CWE-434 (Unrestricted Upload of File with Dangerous Type). The flaw enables attackers to upload malicious PHP files, specifically .phar files containing system command execution payloads, to the files/images directory of the web application. This critical issue carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), highlighting its severity due to high confidentiality, integrity, and availability impacts.

Unauthenticated remote attackers can exploit this vulnerability over the network with low complexity and no user interaction required. By uploading a crafted .phar file to the vulnerable directory, attackers gain the ability to compromise the web application and execute arbitrary system commands on the underlying server, potentially leading to full server takeover.

Advisories from Vulncheck document the unrestricted file upload leading to remote code execution, while a public proof-of-concept exploit is available on Exploit-DB (ID 51464). The vendor's download page at sitemagic.org provides access to software updates, which security practitioners should review for patches addressing this issue.

Details

CWE(s)

Affected Products

sitemagic
sitemagic cms
4.4.3

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Why these techniques?

The vulnerability is an unauthenticated remote code execution via unrestricted upload of dangerous files (.phar with command execution payloads) in a public-facing web application, directly enabling T1190: Exploit Public-Facing Application.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

References