Listen to this Post
How the CVE Works
CVE-2025-21222 is a heap-based buffer overflow vulnerability in the Windows Telephony Service (TAPI). Attackers can exploit this flaw by sending specially crafted network packets to a vulnerable system, triggering memory corruption. Due to improper bounds checking in the serviceβs handling of incoming data, an overflow occurs in dynamically allocated memory (heap), allowing arbitrary code execution with SYSTEM privileges. The exploit requires no user interaction and can be weaponized for remote attacks, making it critical for unpatched Windows systems.
DailyCVE Form
Platform: Windows Telephony Service
Version: Windows 10/11, Server 2019/2022
Vulnerability: Heap buffer overflow
Severity: Critical
Date: 07/03/2025
Prediction: Patch expected by 08/15/2025
What Undercode Say
Analytics:
Get-Service "TapiSrv" | Stop-Service -Force wmic service where "name='TapiSrv'" get State
// Proof-of-concept heap spray snippet
void spray_heap() {
char payload = malloc(SIZE);
memset(payload, 0x41, SIZE);
}
Exploit:
- Crafted RPC calls to `tapisrv.dll`
– Heap grooming for EoP (Elevation of Privilege) - Network-based exploitation via TCP/135
Protection from this CVE
- Disable Telephony Service (
sc config TapiSrv start= disabled) - Apply Microsoft patch (when released)
- Network segmentation for RPC ports
Impact:
- Remote code execution (RCE)
- SYSTEM-level compromise
- Wormable potential
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
