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Vulnerability Intelligence ⚡ CISA KEV Listed CVSS 8.8 (v3.1) EPSS 2.4% (84th %) High (Multi-Source Verified)

CVE-2026-11645

CVE-2026-11645 is a CRITICAL risk security flaw. With a CVSS score of 8.8, it is actively exploited in the wild.

Tech Lead Manager (TLM) Strategic Briefing

Engineering Leadership Context

URGENT OPERATIONAL PRIORITY: CVE-2026-11645 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Active weaponization has been observed in real-world adversary campaigns. Engineering leads must prioritize immediate out-of-band patching or enforce compensating architectural mitigations across all affected systems. Statistical Exploit Likelihood (EPSS): Ranked in the 84.3th percentile globally (30-day weaponization probability: 2.4%).

Key Strategic Takeaways

CISA KEV Catalog: Actively exploited by threat actors in observed intrusions.
CVSS Base Severity: 8.8 (v3.1) — Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Threat Probability: 2.44% (84.3th percentile globally)
CWE Root Cause: CWE-125: Out-of-bounds Read; CWE-787: Out-of-bounds Write

Prioritization & Remediation Guidance

Emergency Remediation: Apply vendor security updates immediately across all public-facing and internal assets.
Telemetry & Threat Sweep: Execute detection queries (KQL/SPL/Sigma) across EDR and firewall logs for exploitation artifacts.
Perimeter Isolation: If patching cannot occur immediately, isolate affected services or apply WAF virtual patching rules.

Deep Technical & Root-Cause Analysis

Security Engineering

Vulnerability Analysis for CVE-2026-11645: Google Chromium V8 Out-of-Bounds Read and Write Vulnerability Root-Cause Flaw Classification: Identified under CWE-125: Out-of-bounds Read, CWE-787: Out-of-bounds Write. This flaw typically manifests when software fails to properly constrain inputs, validate boundaries, or manage memory lifetimes. CVSS Metric Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

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

Exploitation Mechanics & Attack Progression

4-Phase Exploit Sequence

Phase 1 - Attack Surface Discovery & Preconditions: Attacker scans public or internal ingress telemetry to identify reachable instances of the vulnerable service. They enumerate software banners, endpoints, or unauthenticated RPC/HTTP headers to confirm exposure.

Phase 2 - Malformed Payload Delivery: Attacker transmits specially crafted network requests or input data targeting CVE-2026-11645 directly to the vulnerable component.

Phase 3 - Defect Trigger & Execution: The underlying software logic executes the malicious input without proper boundary checks, granting attacker code execution or unauthorized privileged actions.

Phase 4 - Post-Exploitation Movement & Shell Access: The payload spawns an interactive command shell (e.g. bash, sh, powershell.exe, cmd.exe), establishes reverse C2 communication, writes persistent webshells to disk, and executes discovery commands to pivot laterally.

Dedicated Threat Hunt & Movement Detections

Tactical SOC & Threat Hunter Playbook

🔍 Hypothesis & Telemetry Hunt Procedure

› 1. Telemetry Verification (EDR Process Lineage): Query endpoint detection telemetry for web application daemons (e.g. w3wp.exe, nginx, httpd, java, node) spawning shell binaries (cmd.exe, powershell.exe, sh, bash) or utility downloaders (certutil, curl, wget).

› 2. Network Ingress / Egress Inspection: Review reverse proxy, WAF, and firewall logs for anomalous POST/GET requests targeting affected service, followed immediately by unauthorized outbound TCP/UDP connections to external IPs.

› 3. Disk & Webroot Forensics: Scan temporary directories (/tmp/, /var/tmp/, C:\Windows\Temp\) and application webroots for newly dropped webshells, compiled DLLs, or executable scripts created around the timestamp of suspicious requests.

› 4. Session & Identity Auditing: Check authentication and IAM audit logs for newly spawned administrator accounts, service token issuance, or sudden privilege escalation originating from the service host.

⚠️ Lateral Movement & Post-Exploitation Indicators

● Spawning of interactive shells (cmd.exe, powershell.exe, /bin/sh, /bin/bash) from web server or middleware processes
● Outbound network connections initiated from server processes to untrusted external IP addresses on non-standard ports
● Creation of temporary executable artifacts or scripts in %TEMP%, /tmp/, or application document roots
● Execution of system discovery commands (whoami, ipconfig, ifconfig, net user, id, uname -a) by web service accounts
● Attempted persistence via scheduled tasks (schtasks.exe), cron jobs, or registry autorun modifications

🛡️ Production Threat Detection Rules

Ready-to-deploy SIEM / EDR queries

Sigma Rule - CVE-2026-11645 Exploitation & Movement

title: Exploitation and Post-Exploit Movement - CVE-2026-11645
id: 6e1fae2c-229a-5c9c-ad17-c1053e4f1697
status: experimental
description: Detects suspicious process execution, child process anomalies, and command interpreter invocation associated with CVE-2026-11645 exploitation.
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    ParentImage|endswith:
      - '\\w3wp.exe'
      - '\\httpd.exe'
      - '\\nginx.exe'
      - '\\java.exe'
      - '\\node.exe'
      - '\\tomcat.exe'
    Image|endswith:
      - '\\cmd.exe'
      - '\\powershell.exe'
      - '\\pwsh.exe'
      - '\\certutil.exe'
      - '\\whoami.exe'
  condition: selection
level: high
tags:
  - attack.execution
  - attack.t1059
  - cve.cve-2026-11645

Splunk SPL - CVE-2026-11645 Process Anomalies

index=security sourcetype=XmlWinEventLog:Microsoft-Windows-Sysmon/Operational EventCode=1 (ParentImage="*w3wp.exe" OR ParentImage="*httpd.exe" OR ParentImage="*nginx.exe" OR ParentImage="*java.exe" OR ParentImage="*node.exe") (Image="*cmd.exe" OR Image="*powershell.exe" OR Image="*certutil.exe" OR Image="*whoami.exe") | eval cve="CVE-2026-11645" | table _time Computer User ParentImage Image CommandLine cve

Microsoft Sentinel KQL - CVE-2026-11645 Attack Telemetry

// Microsoft Sentinel KQL - Exploitation Detection for CVE-2026-11645
DeviceProcessEvents
| where InitiatingProcessFileName in~ ('w3wp.exe', 'httpd.exe', 'nginx.exe', 'java.exe', 'node.exe', 'tomcat.exe')
| where FileName in~ ('cmd.exe', 'powershell.exe', 'pwsh.exe', 'sh', 'bash', 'whoami.exe', 'certutil.exe')
| extend AssociatedCVE = 'CVE-2026-11645'
| project TimeGenerated, DeviceName, InitiatingProcessFileName, InitiatingProcessCommandLine, FileName, ProcessCommandLine, AccountName, AssociatedCVE

Authoritative Telemetry & Scoring

National Vulnerability Database NVD 2.0

CVSS Base Score: 8.8

Framework: NVD General

CWE Classification:

CWE-125: Out-of-bounds Read
CWE-787: Out-of-bounds Write

CISA KEV Catalog Exploited

Date Added: Recorded

Federal Due Date: Immediate

FIRST EPSS Model v3 Model

Exploit Probability: 2.44%

Global Percentile: 84.3th %

Predicts probability of weaponization in the next 30 days based on real-world threat telemetry.

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