Critical & High-Severity CVEs
Log4Shell - CVE-2021-44228
CVSS Score: 10.0 (Critical)
Affected: Apache Log4j 2.0-beta9 through 2.15.0
Description: Remote code execution vulnerability in Log4j logging library. Allows attackers to execute arbitrary code by logging a specially crafted string.
Quick Fix:
• Upgrade to Log4j 2.17.1 or later immediately
• If upgrade not possible, set system property: -Dlog4j2.formatMsgNoLookups=true
• Remove JndiLookup class: zip -q -d log4j-core-*.jar org/apache/logging/log4j/core/lookup/JndiLookup.class
# Maven - Update pom.xml
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.17.1</version>
</dependency>
Spring4Shell - CVE-2022-22965
CVSS Score: 9.8 (Critical)
Affected: Spring Framework 5.3.0-5.3.17, 5.2.0-5.2.19, and older versions
Description: Remote code execution in Spring Framework via data binding on JDK 9+.
Quick Fix:
• Upgrade Spring Framework to 5.3.18+ or 5.2.20+
• Upgrade Spring Boot to 2.6.6+ or 2.5.12+
• Apply mitigations if immediate upgrade impossible
# Check Spring version
mvn dependency:tree | grep spring-core
# Update to fixed version in pom.xml
<spring.version>5.3.18</spring.version>
Heartbleed - CVE-2014-0160
CVSS Score: 7.5 (High)
Affected: OpenSSL 1.0.1 through 1.0.1f
Description: Buffer over-read in OpenSSL's TLS heartbeat extension allowing attackers to read memory contents.
Quick Fix:
• Update OpenSSL to version 1.0.1g or later
• Recompile any software linked against vulnerable OpenSSL
• Revoke and reissue all SSL certificates
• Reset all user passwords
# Check OpenSSL version
openssl version -a
# Update on Ubuntu/Debian
sudo apt-get update
sudo apt-get install openssl libssl-dev
# Update on CentOS/RHEL
sudo yum update openssl
ProxyShell - CVE-2021-34473, CVE-2021-34523, CVE-2021-31207
CVSS Score: 9.8 (Critical)
Affected: Microsoft Exchange Server 2013, 2016, 2019
Description: Chain of vulnerabilities allowing unauthenticated remote code execution.
Quick Fix:
• Apply Microsoft security updates immediately
• Install Exchange Server 2019 CU11 or CU10 with security update
• Install Exchange Server 2016 CU22 or CU21 with security update
• Monitor for signs of compromise
Sudo Heap Overflow - CVE-2021-3156 (Baron Samedit)
CVSS Score: 7.8 (High)
Affected: Sudo versions 1.8.2 through 1.8.31p2 and 1.9.0 through 1.9.5p1
Description: Heap-based buffer overflow allowing local privilege escalation to root.
Quick Fix:
• Update sudo to version 1.9.5p2 or later
• Verify fix with: sudoedit -s / (should error, not segfault)
# Check sudo version
sudo --version
# Update on Ubuntu/Debian
sudo apt update && sudo apt upgrade sudo
# Update on CentOS/RHEL
sudo yum update sudo
# Verify the fix
sudoedit -s /
# Should show: "sudoedit: /: not a regular file"
PrintNightmare - CVE-2021-34527
CVSS Score: 8.8 (High)
Affected: Windows Print Spooler service
Description: Remote code execution in Windows Print Spooler service.
Quick Fix:
• Apply Microsoft security patches immediately
• Disable Print Spooler service if not needed: Stop-Service -Name Spooler -Force
• Disable inbound remote printing through Group Policy
# PowerShell: Stop Print Spooler
Stop-Service -Name Spooler -Force
Set-Service -Name Spooler -StartupType Disabled
# Check if service is disabled
Get-Service -Name Spooler
Shellshock - CVE-2014-6271
CVSS Score: 10.0 (Critical)
Affected: GNU Bash through 4.3
Description: Bash shell allows remote attackers to execute arbitrary code via crafted environment variables.
Quick Fix:
• Update Bash to patched version immediately
• Test for vulnerability: env x='() { :;}; echo vulnerable' bash -c "echo test"
# Test for vulnerability
env x='() { :;}; echo vulnerable' bash -c "echo test"
# If "vulnerable" appears, you're affected
# Update Bash
# Ubuntu/Debian
sudo apt-get update && sudo apt-get install --only-upgrade bash
# CentOS/RHEL
sudo yum update bash
# Verify fix
bash --version
Dirty COW - CVE-2016-5195
CVSS Score: 7.8 (High)
Affected: Linux kernel versions 2.6.22 through 4.8.3
Description: Race condition in memory subsystem allowing local privilege escalation.
Quick Fix:
• Update Linux kernel to patched version
• Reboot system after kernel update
# Check kernel version
uname -r
# Update kernel (Ubuntu/Debian)
sudo apt-get update && sudo apt-get dist-upgrade
# Update kernel (CentOS/RHEL)
sudo yum update kernel
# Reboot required
sudo reboot
Web Application CVEs
WordPress File Manager - CVE-2020-25213
CVSS Score: 9.8 (Critical)
Affected: File Manager plugin versions < 6.9
Description: Unauthenticated arbitrary file upload and remote code execution.
Quick Fix:
• Update File Manager plugin to version 6.9 or later
• Or remove the plugin if not actively used
• Check for unauthorized files in wp-content/plugins/
Drupal Core - CVE-2018-7600 (Drupalgeddon2)
CVSS Score: 9.8 (Critical)
Affected: Drupal 7.x and 8.x before 7.58 and 8.5.1
Description: Remote code execution via multiple attack vectors.
Quick Fix:
• Update Drupal core immediately
• Run: composer update drupal/core --with-dependencies
• Check for signs of compromise
Additional Resources
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• MITRE CVE Database
• National Vulnerability Database (NVD)
• CISA Known Exploited Vulnerabilities
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