CVE-2021-47964

Description

Schlix CMS 2.2.6-6 contains a remote code execution vulnerability that allows authenticated attackers to execute arbitrary PHP code by uploading malicious extension packages through the block manager. Attackers can upload a crafted ZIP file containing PHP code in the packageinfo.inc file and trigger execution by accessing the About tab of the installed extension.

Overview

State

—

Assigner (CNA)

—

CVSS severity

high

CVSS score

8.8 / 10

CVSS vector

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

Effective score

8.8 / 10 HIGH source: CNA overview

CWE(s)

—

Reserved

—

Published

—

Last updated

—

Source

https://www.tenable.com/cve/CVE-2021-47964

Linked Threat

CVE-2021-47964 — CVE-2021-47964

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published

2026-05-15 19:16:56 UTC

NVD last modified

2026-05-18 17:26:40 UTC

NVD CVSS v3.1

8.8 / 10 HIGH source: disclosure@vulncheck.com

NVD CVSS vector

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

Exploitability subscore

2.8 / 10

Impact subscore

5.9 / 10

EPSS score

0.0027 (probability of exploitation in next 30 days)

EPSS percentile

50.49% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24

NVD-assigned CWE(s): CWE-94 (differs from the CNA list above)

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID

EUVD-2021-34817

Assigner

VulnCheck

Published

May 15, 2026, 6:36:30 PM

Updated

May 18, 2026, 4:02:50 PM

EUVD base score (CVSS 4.0)

8.7 / 10
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

EUVD-reported EPSS

0.2700

Vendors

Schlix

Products

Schlix CMS (2.2.6-6)

Aliases

GHSA-r3mq-4wxp-p8vq

ENISA description: Schlix CMS 2.2.6-6 contains a remote code execution vulnerability that allows authenticated attackers to execute arbitrary PHP code by uploading malicious extension packages through the block manager. Attackers can upload a crafted ZIP file containing PHP code in the packageinfo.inc file and trigger execution by accessing the About tab of the installed extension.

Vendor references (0)

References embedded in the original CVE record by the assigning CNA.

None in the CVE record.

Web references (7)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

• https://nvd.nist.gov/vuln/detail/CVE-2021-47964 tenable:nvd.nist.gov
• https://www.cve.org/CVERecord?id=CVE-2021-47964 tenable:www.cve.org
• https://www.exploit-db.com/exploits/49838 tenable:www.exploit-db.com
• https://www.first.org/epss/ tenable:www.first.org
• https://www.schlix.com/ tenable:www.schlix.com
• https://www.schlix.com/downloads/schlix-cms/schlix-cms-v2.2.6-6.zip tenable:www.schlix.com
• https://www.vulncheck.com/advisories/schlix-cms-6-remote-code-execution-via-core-blockmanager tenable:www.vulncheck.com

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

• Oracle Critical Patch Update, April 2026 Security Update Review
  web:blog.qualys.com

  Oracle released its second quarterly edition of this year's Critical Patch Update. The update received patches for 481 security vulnerabilities.

  2026-05-26 02:56 UTC
• CWE - Common Weakness Enumeration
  web:cwe.mitre.org

  Common Weakness Enumeration (CWE) is a list of software and hardware weaknesses.

  2026-05-26 02:56 UTC
• Security Update Guide - Microsoft
  web:msrc.microsoft.com

  The Microsoft Security Response Center (MSRC) investigates all reports of security vulnerabilities affecting Microsoft products and services, and provides the information here as part of the ongoing effort to help you manage security risks and help keep your systems protected.

  2026-05-26 02:56 UTC
• How to Use Known Issue Rollback to Fix Problems Caused by Windows ...
  web:petri.com

  If a Group Policy setting is available to roll back a fix , it is included in the Windows Update KB article and release notes as a mitigation for a known issue.

  2026-05-26 02:56 UTC
• Fix RDP Connection Error 'CredSSP Encryption Oracle Remediation'
  web:woshub.com

  The Encryption Oracle Remediation policy provides 3 levels of mitigation for the CredSSP vulnerability: Force Updated Clients - the most secure mode, which blocks vulnerable computer connections. If this option is enabled on the RDP host, it will block RDP connections from client computers with a vulnerable version of CredSSP.

  2026-05-26 02:56 UTC
• A guide to vulnerability remediation vs mitigation | @Bugcrowd
  web:www.bugcrowd.com

  Vulnerability mitigation is typically considered a temporary or interim solution. While mitigation measures can reduce the immediate risk associated with vulnerabilities, they may not provide a permanent fix . Organizations should aim to prioritize and plan for complete vulnerability remediation whenever feasible and allocate resources accordingly.

  2026-05-26 02:56 UTC
• Known Exploited Vulnerabilities Catalog - CISA
  web:www.cisa.gov

  For the benefit of the cybersecurity community and network defenders—and to help every organization better manage vulnerabilities and keep pace with threat activity—CISA maintains the authoritative source of vulnerabilities that have been exploited in the wild. Organizations should use the KEV catalog as an input to their vulnerability management prioritization framework.

  2026-05-26 02:56 UTC
• National Vulnerability Database | NIST
  web:www.nist.gov

  NIST maintains the National Vulnerability Database (NVD), a repository of information on software and hardware flaws that can compromise computer security. This is a key piece of the nation's cybersecurity infrastructure.

  2026-05-26 02:56 UTC
• Critical Patch Updates, Critical Security Patch Updates ... - Oracle
  web:www.oracle.com

  Critical Security Patch Updates Critical Security Patch Updates provide security patches for supported Oracle on-premises products. A Critical Security Patch Update provides targeted, high-priority security fixes in a smaller, more focused format, making them easier to apply with minimal disruption.

  2026-05-26 02:56 UTC
• 5 Best Ways to Repair SCCM Client Agent - Prajwal Desai
  web:www.prajwaldesai.com

  Discover effective methods to repair SCCM client agent, including PowerShell scripts, command line, Right-Click Tools, and Advanced Insights for seamless troubleshooting.

  2026-05-26 02:56 UTC

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