CVE-2026-77975
CVE-2026-77975 is a HIGH risk security flaw. With a CVSS score of 7.1, it presents potential exposure requiring defensive validation.
Tech Lead Manager (TLM) Strategic Briefing
ELEVATED EXPOSURE: CVE-2026-77975 represents a High severity vulnerability (CVSS 7.1). Engineering managers should evaluate perimeter exposure, verify whether affected components are exposed to untrusted ingress, and schedule remediation during the next standard maintenance release. Statistical Exploit Likelihood (EPSS): Ranked in the 7.7th percentile globally (30-day weaponization probability: 0.2%).
- CISA KEV Catalog: No active in-the-wild exploitation entry.
- CVSS Base Severity: 7.1 (v3.1) — Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- EPSS Threat Probability: 0.18% (7.7th percentile globally)
- CWE Root Cause: CWE-312
- Prioritized Patching: Schedule patch deployment during the next maintenance window or sprint release.
- Exposure Assessment: Audit network segmentation to ensure vulnerable endpoints are restricted from untrusted ingress.
Deep Technical & Root-Cause Analysis
Vulnerability Analysis for CVE-2026-77975: Ebyte NA111-M Root-Cause Flaw Classification: Identified under CWE-312. This flaw typically manifests when software fails to properly constrain inputs, validate boundaries, or manage memory lifetimes. CVSS Metric Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X.
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Exploitation Mechanics & Attack Progression
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-2026-77975 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
🔍 Hypothesis & Telemetry Hunt Procedure
⚠️ 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 queriestitle: Exploitation and Post-Exploit Movement - CVE-2026-77975
id: 6521451a-23a0-5e2d-9666-0a565eb2967d
status: experimental
description: Detects suspicious process execution, child process anomalies, and command interpreter invocation associated with CVE-2026-77975 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-2026-77975index=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-2026-77975" | table _time Computer User ParentImage Image CommandLine cve// Microsoft Sentinel KQL - Exploitation Detection for CVE-2026-77975
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-2026-77975'
| project TimeGenerated, DeviceName, InitiatingProcessFileName, InitiatingProcessCommandLine, FileName, ProcessCommandLine, AccountName, AssociatedCVEAuthoritative Telemetry & Scoring
CVSS Base Score: 7.1
Framework: NVD General
- CWE-312
No active weaponization confirmed in the CISA Known Exploited Vulnerabilities catalog to date.
Exploit Probability: 0.18%
Global Percentile: 7.7th %
Predicts probability of weaponization in the next 30 days based on real-world threat telemetry.