What is the CVSS score of CVE-2021-47900?

CVE-2021-47900 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.3%.

Which versions of PHP are affected by CVE-2021-47900?

Gila CMS instances running versions prior to 2.0.0 are vulnerable to unauthenticated remote code execution with a CVSS score of 9.8, meaning attackers can take complete control of affected systems…

Is there a public PoC exploit available for CVE-2021-47900?

Yes, a public proof-of-concept exploit is available for CVE-2021-47900. Prioritise patching immediately. EPSS: 0.3%.

How to fix or mitigate CVE-2021-47900?

Within 24 hours: Inventory all systems running Gila CMS and identify version numbers; immediately isolate or take offline any instances running versions prior to 2.0.0 if they are internet-facing. Within 7 days: Upgrade all Gila CMS installations to version 2.0.0 or later, or implement compensating controls (WAF rules, network access restrictions). Within 30 days: Conduct forensic review of access logs for affected systems to identify potential compromise; deploy monitoring and alerting for suspicious HTTP header patterns.

PHP CVE-2021-47900

CRITICAL

PHP Remote File Inclusion (CWE-98)

2026-01-27 disclosure@vulncheck.com

PHP RCE

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:55 vuln.today

PoC Detected

Jan 29, 2026 - 16:31 vuln.today

Public exploit code

CVE Published

Jan 27, 2026 - 16:16 nvd

CRITICAL 9.8

DescriptionCVE.org

Gila CMS versions prior to 2.0.0 contain a remote code execution vulnerability that allows unauthenticated attackers to execute arbitrary system commands through manipulated HTTP headers. Attackers can inject PHP code in the User-Agent header with shell_exec() to run system commands by sending crafted requests to the admin endpoint.