CVE-2026-21509
HIGH KEVMicrosoft 365 Apps and Office - Security Feature Bypass via Untrusted Input
Title source: llmExploitation Summary
CVE-2026-21509 is actively exploited and listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added January 26, 2026. EIP tracks 13 public exploits from researchers including XiaomingX, gavz, kimstars.
AI-analyzed exploit summary This repository contains a functional exploit PoC for CVE-2026-21509, leveraging a novel approach combining fluid dynamics theory with NFS protocol exploitation. The code implements a temporal vortex attack using RPC fragmentation and energy cascade techniques to achieve remote code execution.
Description
Reliance on untrusted inputs in a security decision in Microsoft Office allows an unauthorized attacker to bypass a security feature locally.
Exploits (13)
This repository contains a functional exploit PoC for CVE-2026-21509, leveraging a novel approach combining fluid dynamics theory with NFS protocol exploitation. The code implements a temporal vortex attack using RPC fragmentation and energy cascade techniques to achieve remote code execution.
This repository provides a harmless, non-exploit Proof of Concept for CVE-2026-21509, a Microsoft Office security feature bypass vulnerability. It generates a harmless DOCX file containing dummy embedded OLE components for defensive research, EDR/AV visibility testing, and training purposes.
This is a working PoC for CVE-2026-21509, a Microsoft Office OLE security feature bypass vulnerability. It generates a DOCX file with an embedded OLE object to test the bypass, requiring user interaction to open the file.
This repository contains a proof-of-concept exploit for CVE-2026-21509, leveraging a temporal resonance technique to bypass Microsoft Office OLE validation. The exploit uses a 33-layer manifold to achieve speculative execution, evading detection mechanisms like AMSI/EDR.
This PoC exploits a vulnerability in NFS (CVE-2026-21509) using a novel approach based on fluid dynamics (CTT-Navier-Stokes mapping) to craft RPC fragments. It implements Theorem 4.2 energy cascade for evasion and payload delivery, targeting NFS protocol procedures.
This repository provides a YARA rule and a Python script to detect MS Office files containing 'Shell.Explorer.1' OLE objects, which are indicators of potential exploitation of CVE-2026-21509. The script analyzes OpenXML, OLE/CFB, and RTF documents for the presence of the specific CLSID associated with the vulnerability.
This PoC exploits CVE-2026-21509 by bypassing OLE/COM mitigations in Microsoft Office via a 33-layer energy cascade technique, achieving RCE through temporal resonance manipulation in OLE2 objects.
This repository contains PowerShell scripts for detecting and remediating CVE-2026-21509 by checking and setting registry values related to Microsoft Office COM compatibility. It does not include exploit code but provides mitigation steps.
This repository contains a functional PoC for CVE-2026-21509, a Microsoft Office security feature bypass vulnerability. The PoC generates a harmless DOCX file with dummy OLE components to simulate structural markers related to the vulnerability, useful for defensive research and EDR/AV visibility testing.
The repository contains a functional Python script that generates a malicious DOCX file exploiting CVE-2026-21509 by embedding a crafted OLE compound file with a user-specified CLSID. The script constructs a valid Office Open XML document with required metadata and relationships.
This PowerShell script applies a kill-bit registry modification to mitigate CVE-2026-21509 in Microsoft Office 2016 by disabling a vulnerable COM object. It includes functionality to check, apply, and remove the kill-bit, as well as verify relevant KB updates.
This repository contains a PowerShell script that mitigates CVE-2026-21509, a Microsoft Office Security Feature Bypass Vulnerability, by applying registry keys to block a vulnerable COM component. The script detects Office installation types and applies the necessary registry changes to prevent exploitation.
The repository contains a Windows shortcut (LNK) file that exploits CVE-2026-21509 by executing 'calc.exe' via a crafted path. This is a functional PoC demonstrating arbitrary code execution through a malicious LNK file.
References (4)
Scores
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H