CVE-2023-21671

Q: What is the severity of CVE-2023-21671?

CVE-2023-21671 has a CVSS score of 9.3 (CRITICAL). This vulnerability allows memory corruption in Qualcomm's Core system during syscall for Sectools Fuse comparison feature. Attackers could potentially execute arbitrary code with kernel privileges on affected devices. This affects Android devices using Qualcomm chipsets.

9.3 CRITICAL

📋 TL;DR

This vulnerability allows memory corruption in Qualcomm's Core system during syscall for Sectools Fuse comparison feature. Attackers could potentially execute arbitrary code with kernel privileges on affected devices. This affects Android devices using Qualcomm chipsets.

💻 Affected Systems

Products:

Qualcomm Snapdragon chipsets
Android devices with Qualcomm processors

Versions: Multiple Qualcomm chipset versions (specifics in vendor advisory)

Operating Systems: Android

Default Config Vulnerable: ⚠️ Yes

Notes: Affects Android devices with vulnerable Qualcomm chipsets; requires local access or malicious app installation.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete device compromise with kernel-level code execution, allowing persistent root access, data theft, and device control.

🟠

Likely Case

Privilege escalation to kernel level, enabling installation of persistent malware, data exfiltration, and bypassing security controls.

🟢

If Mitigated

Limited impact if devices are patched, have SELinux enforcing, and proper app sandboxing; kernel-level access still dangerous.

🌐 Internet-Facing: MEDIUM

🏢 Internal Only: HIGH

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access or malicious app; memory corruption vulnerabilities often lead to reliable exploitation.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Refer to Qualcomm November 2023 security bulletin for specific chipset patches

Vendor Advisory: https://www.qualcomm.com/company/product-security/bulletins/november-2023-bulletin

Restart Required: Yes

Instructions:

1. Check Qualcomm bulletin for your chipset model. 2. Obtain firmware update from device manufacturer. 3. Apply Android security patch containing the fix. 4. Reboot device.

🔧 Temporary Workarounds

Restrict app installations

android

Prevent installation of untrusted apps that could exploit the vulnerability

adb shell settings put secure install_non_market_apps 0

Enable SELinux enforcing

android

Ensure SELinux is in enforcing mode to limit kernel exploitation impact

adb shell getenforce
adb shell setenforce 1

🧯 If You Can't Patch

Isolate affected devices from sensitive networks and data
Implement strict app allowlisting and disable unknown sources

🔍 How to Verify

Check if Vulnerable:

Check Android security patch level and Qualcomm chipset version against November 2023 patches

Check Version:

adb shell getprop ro.build.version.security_patch

Verify Fix Applied:

Verify Android security patch level is November 2023 or later and check Qualcomm firmware version

📡 Detection & Monitoring

Log Indicators:

Kernel panic logs
Sectools Fuse syscall anomalies
Unexpected privilege escalation attempts

Network Indicators:

Unusual outbound connections from system processes
Suspicious inter-process communication

SIEM Query:

source="android_kernel" AND (event="panic" OR event="oops") OR process="sectools" AND action="fuse_compare"

📊 Metadata

CVE ID: CVE-2023-21671

CVSS v3 Score: 9.3 (CRITICAL)

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

CWE: CWE-20

Published: November 7, 2023

Last Updated: August 11, 2025

🔗 References

https://www.qualcomm.com/company/product-security/bulletins/november-2023-bulletin Vendor Advisory
https://www.qualcomm.com/company/product-security/bulletins/november-2023-bulletin Vendor Advisory

📋 TL;DR

💻 Affected Systems

📦 What is this software?

Fastconnect 6700 Firmware by Qualcomm

Fastconnect 6900 Firmware by Qualcomm

Qca6391 Firmware by Qualcomm

Qcm6490 Firmware by Qualcomm

Qcs6490 Firmware by Qualcomm

Qsm8350 Firmware by Qualcomm

Sd888 Firmware by Qualcomm

Sm7315 Firmware by Qualcomm

Sm7325p Firmware by Qualcomm

Snapdragon 778g 5g Mobile Platform Firmware by Qualcomm

Snapdragon 778g 5g Mobile Platform Firmware by Qualcomm

Snapdragon 780g 5g Mobile Platform Firmware by Qualcomm

Snapdragon 782g Mobile Platform Firmware by Qualcomm

Snapdragon 7c\+ Gen 3 Compute Firmware by Qualcomm

Snapdragon 888 5g Mobile Platform Firmware by Qualcomm

Snapdragon 888 5g Mobile Platform Firmware by Qualcomm

Video Collaboration Vc3 Platform Firmware by Qualcomm

Wcd9370 Firmware by Qualcomm

Wcd9375 Firmware by Qualcomm

Wcd9380 Firmware by Qualcomm

Wcd9385 Firmware by Qualcomm

Wcn6740 Firmware by Qualcomm

Wsa8830 Firmware by Qualcomm

Wsa8835 Firmware by Qualcomm