Getsimplecms
CVE-2021-28976
HIGH
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V5 - File Handling File type validation, storage isolation
MITRE ATT&CK
2 techniques across 2 tactics: Command and Control, Persistence The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 7.2 (HIGH). Attack characteristics: network attack vector, low complexity, high privileges required, no user interaction not required. |
| Exploit ScenarioDerived | A remote attacker could upload malicious files that can be executed on the server by sending crafted requests to the affected application. |
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Alert meAnalysisAI
Remote Code Execution vulnerability in GetSimpleCMS before 3.3.16 in admin/upload.php via phar filess. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate file types server-side, store uploads outside webroot, use random filenames, scan for malware.
Affects your stack
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Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Unrestricted File Upload (CWE-434), which allows attackers to upload malicious files that can be executed on the server. Remote Code Execution vulnerability in GetSimpleCMS before 3.3.16 in admin/upload.php via phar filess. Affected products include: Get-Simple Getsimplecms. Version information: before 3.3.16.
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Severity by source
AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
Remote Code Execution vulnerability in GetSimpleCMS before 3.3.16 in admin/upload.php via phar filess.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Exploit-DB
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Malicious file upload attacks exploit insufficient validation when web applications accept user-provided files.
Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.
Affected Products (CPE)NVD
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