Top 10 Most Exploited Vulnerabilities of 2026

Based on CISA's Known Exploited Vulnerabilities (KEV) catalog and Precogs Threat Intelligence, these are the 10 most weaponized vulnerabilities of the year. Threat actors are aggressively targeting these flaws to gain initial access, deploy ransomware, and establish persistence across enterprise networks.

Verified by Precogs Threat Research

Analysis by Rajnish Sharma • Last Updated: March 2026

Ivanti Connect Secure Zero-Day (CVE-2026-0012)

An unauthenticated command injection vulnerability in Ivanti VPN gateways that allowed attackers to execute arbitrary commands with root privileges.

Real World Case Study

In Q1 2026, multiple state-sponsored threat groups weaponized this vulnerability to deploy custom webshells (like GLASSTOKEN) into corporate networks. Attackers evaded legacy detection by patching the logging services on compromised devices, allowing them to traverse laterally and steal Active Directory credentials without triggering SIEM alerts.

The Precogs AI Fix

Precogs AI detects the insecure exec() calls in Python-based web appliances and auto-patches the handler to use strict allowlist validation for shell arguments.

Notable CVEs in this Class

Palo Alto Networks PAN-OS GlobalProtect Flaw (CVE-2026-3400)

A pre-authentication OS command injection vulnerability in the GlobalProtect feature of PAN-OS devices.

Real World Case Study

Threat actors exploited this flaw to install backdoors via a novel cronjob persistence mechanism. Operation 'Midnight Horizon' affected over 4,000 firewalls globally within 48 hours of exploit publication, leading to massive data exfiltration from healthcare organizations.

The Precogs AI Fix

Precogs AI identifies unvalidated input paths in C/C++ firmware codebases and implements rigid input sanitization libraries before compilation.

Notable CVEs in this Class

Progress MOVEit Transfer SQLi (CVE-2026-2311)

A zero-day SQL injection vulnerability in the MOVEit Transfer web application leading to unauthenticated remote code execution.

Real World Case Study

The CL0P ransomware syndicate utilized an automated exploitation script to harvest sensitive data from thousands of enterprise MOVEit instances. The attack targeted the guest access portal, injecting a malicious payload that extracted database secrets and generated a persistent admin session.

The Precogs AI Fix

Precogs AI automatically scans C# and ASP.NET backends for concatenated SQL queries and replaces them with parameterized Entity Framework LINQ queries.

Notable CVEs in this Class

Microsoft SharePoint Server RCE (CVE-2026-2144)

An insecure deserialization vulnerability allowing an authenticated attacker to execute arbitrary code on the SharePoint server.

Real World Case Study

Ransomware operators used compromised low-privileged accounts to trigger a deserialization chain via a crafted XML payload. This bypassed AMSI (Anti-Malware Scan Interface) and granted SYSTEM access, resulting in the encryption of massive corporate document repositories.

The Precogs AI Fix

Precogs AI flags the use of insecure TypeNameHandling.Auto configurations in NewtonSoft.Json and automatically applies strict JSON schemas and SerializationBinders.

Notable CVEs in this Class

Apache ActiveMQ RCE (CVE-2026-3822)

A critical remote code execution vulnerability related to the insecure deserialization of OpenWire protocol packets.

Real World Case Study

The Godzilla webshell was heavily deployed across exposed ActiveMQ instances via port 61616. Threat actors utilized this access to mine cryptocurrencies and deploy the HelloKitty ransomware. The exploit bypassed traditional WAFs since it communicated over a proprietary binary protocol.

The Precogs AI Fix

Precogs AI enforces class allowlisting in Java ObjectInputStream implementations, preventing unauthorized class instantiation during network payload parsing.

Notable CVEs in this Class

Citrix NetScaler ADC Buffer Overflow (CVE-2026-4911)

A memory corruption vulnerability (buffer overflow) in the NetScaler ADC gateway process (nsppe).

Real World Case Study

Nicknamed 'CitrixBleed v2', this vulnerability leaked session tokens directly from process memory without generating application logs. Attackers replayed these session tokens to bypass MFA and access internal corporate resources via the gateway.

The Precogs AI Fix

Precogs Binary SAST detects unsafe memory copy operations in compiled C binaries and generates AutoFix patches utilizing bounds-checked alternatives like strlcpy().

Notable CVEs in this Class

Atlassian Confluence Template Injection (CVE-2026-2251)

A Server-Side Template Injection (SSTI) vulnerability in the Confluence Data Center allowing unauthenticated code execution.

Real World Case Study

Attackers exploited the OGNL template engine by injecting malicious expressions into the URI parameters of specific endpoints. This allowed adversaries to drop the 'Cerberus' rootkit onto the host operating system, leading to sustained access even after the Confluence application was patched.

The Precogs AI Fix

Precogs AI identifies unsafe template rendering patterns in Java Spring and Struts applications, injecting strict template evaluation sandboxes.

Notable CVEs in this Class

VMware vCenter Server Authentication Bypass (CVE-2026-3422)

A missing authentication check in the vCenter Server DCE/RPC protocol implementation.

Real World Case Study

State-sponsored actors utilized this flaw to take complete control over hypervisor infrastructure across target organizations in the banking sector. The attackers deployed stealthy VMs that siphoned memory states from neighboring financial transaction servers.

The Precogs AI Fix

Precogs AI validates end-to-end authentication flows across microservices and automatically wraps unprotected RPC endpoints with centralized AuthZ middleware.

Notable CVEs in this Class

Fortinet FortiOS SSL-VPN Heap Overflow (CVE-2026-2133)

A heap-based buffer overflow vulnerability in the FortiOS SSL-VPN daemon.

Real World Case Study

Discovered by threat intelligence teams observing anomalous crashes in the sslvpnd process. Investigation revealed a targeted campaign where attackers sent specially crafted HTTP requests to overwrite heap metadata, redirecting execution flow to a malicious payload stored in memory.

The Precogs AI Fix

Precogs AI's binary analyzer detects the missing integer bounding logic before the malloc() call, preventing the overflow condition entirely.

Notable CVEs in this Class

#10

Jenkins CLI Arbitrary File Read (CVE-2026-2389)

A path traversal and arbitrary file read vulnerability via the Jenkins CLI expandArguments function.

Real World Case Study

Initial Access Brokers (IABs) mass-scanned the internet for exposed Jenkins controllers, utilizing this flaw to read the credentials.xml file and extract encrypted secrets. Attackers then brute-forced the master key locally, gaining access to the entire CI/CD pipeline infrastructure and injecting malicious code into downstream builds.

The Precogs AI Fix

Precogs AI identifies insecure argument parsers handling filepath inputs and enforces path canonicalization (realpath validation) via AutoFix PRs.

Notable CVEs in this Class

Frequently Asked Questions

What makes a vulnerability 'most exploited'?

A vulnerability is considered highly exploited when threat actors actively use it in the wild to compromise systems. This metric goes beyond CVSS scores by measuring actual empirical exploitation by ransomware gangs, APTs, and automated botnets, rather than theoretical severity.

How frequently is the CISA KEV catalog updated?

CISA updates the KEV catalog continuously as new active exploitation evidence emerges. However, zero-day vulnerabilities are often exploited for weeks or months before officially entering the catalog or receiving a CVE identifier.