CVE-2025-21477

Q: What is the severity of CVE-2025-21477?

CVE-2025-21477 has a CVSS score of 7.5 (HIGH). This vulnerability allows attackers to cause a Denial of Service (DoS) condition in affected Qualcomm systems by sending specially crafted CCCH data with invalid length. The vulnerability affects mobile devices and telecommunications infrastructure using Qualcomm chipsets. Attackers can temporarily disrupt service availability.

7.5 HIGH

Denial of Service

📋 TL;DR

This vulnerability allows attackers to cause a Denial of Service (DoS) condition in affected Qualcomm systems by sending specially crafted CCCH data with invalid length. The vulnerability affects mobile devices and telecommunications infrastructure using Qualcomm chipsets. Attackers can temporarily disrupt service availability.

💻 Affected Systems

Products:

Qualcomm chipsets with CCCH processing capabilities

Versions: Specific versions not publicly detailed; refer to Qualcomm August 2025 security bulletin

Operating Systems: Android and other mobile OS using Qualcomm chipsets

Default Config Vulnerable: ⚠️ Yes

Notes: Affects systems processing CCCH (Common Control Channel) data in mobile networks; exact product list requires checking Qualcomm advisory.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete service disruption for affected mobile devices or network equipment, potentially affecting multiple users in a geographic area.

🟠

Likely Case

Temporary service interruption for individual devices or localized network segments, requiring device reboot or network equipment restart.

🟢

If Mitigated

Minimal impact with proper network segmentation and monitoring; service restored quickly after detection.

🌐 Internet-Facing: MEDIUM - Attackers could target exposed network interfaces, but requires specific knowledge of affected systems.

🏢 Internal Only: LOW - Requires access to internal network segments and knowledge of vulnerable systems.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires sending malformed CCCH data to vulnerable systems; no public exploit code available as of analysis.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Refer to Qualcomm August 2025 security bulletin for specific firmware versions

Vendor Advisory: https://docs.qualcomm.com/product/publicresources/securitybulletin/august-2025-bulletin.html

Restart Required: Yes

Instructions:

1. Check Qualcomm advisory for affected chipset models. 2. Obtain updated firmware from device manufacturer. 3. Apply firmware update following manufacturer instructions. 4. Reboot affected devices.

🔧 Temporary Workarounds

Network Traffic Filtering

all

Implement network filtering to block malformed CCCH packets at network perimeter

Rate Limiting

all

Implement rate limiting on CCCH traffic to reduce DoS impact

🧯 If You Can't Patch

Implement strict network segmentation to isolate vulnerable systems
Deploy network monitoring to detect abnormal CCCH traffic patterns

🔍 How to Verify

Check if Vulnerable:

Check device firmware version against Qualcomm advisory; examine system logs for CCCH processing errors

Check Version:

Device-specific commands vary by manufacturer; typically 'adb shell getprop ro.build.fingerprint' for Android devices

Verify Fix Applied:

Verify firmware version matches patched version from Qualcomm bulletin; test CCCH processing functionality

📡 Detection & Monitoring

Log Indicators:

CCCH processing errors
Unexpected service restarts
Memory allocation failures in network stack

Network Indicators:

Abnormal CCCH packet sizes
Sudden increase in control channel traffic
Service disruption patterns

SIEM Query:

source="network_logs" AND ("CCCH" OR "control channel") AND (error OR failure OR restart)

📊 Metadata

CVE ID: CVE-2025-21477

CVSS v3 Score: 7.5 (HIGH)

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

CWE: CWE-20

EPSS Score: 0.08% exploit probability (23.5th percentile)

Published: August 6, 2025

Last Updated: August 20, 2025

🔗 References

https://docs.qualcomm.com/product/publicresources/securitybulletin/august-2025-bulletin.html Vendor Advisory

📋 TL;DR

💻 Affected Systems

📦 What is this software?

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Fastconnect 6200 Firmware by Qualcomm

Fastconnect 6700 Firmware by Qualcomm

Fastconnect 6800 Firmware by Qualcomm

Fastconnect 6900 Firmware by Qualcomm

Fastconnect 7800 Firmware by Qualcomm

Qca6391 Firmware by Qualcomm

Qca6574a Firmware by Qualcomm

Qca6584au Firmware by Qualcomm

Qca6595au Firmware by Qualcomm

Qca6696 Firmware by Qualcomm

Qca6698aq Firmware by Qualcomm

Qca8081 Firmware by Qualcomm

Qca8337 Firmware by Qualcomm

Qcc710 Firmware by Qualcomm

Qcm5430 Firmware by Qualcomm

Qcm6490 Firmware by Qualcomm

Qcn6024 Firmware by Qualcomm

Qcn6224 Firmware by Qualcomm

Qcn6274 Firmware by Qualcomm

Qcn9024 Firmware by Qualcomm

Qcs5430 Firmware by Qualcomm

Qcs6490 Firmware by Qualcomm

Qcs8550 Firmware by Qualcomm

Qfw7114 Firmware by Qualcomm

Qfw7124 Firmware by Qualcomm

Sdx55 Firmware by Qualcomm

Sdx57m Firmware by Qualcomm

Sg8275p Firmware by Qualcomm

Sm7250p Firmware by Qualcomm

Sm7325p Firmware by Qualcomm

Sm7675 Firmware by Qualcomm

Sm7675p Firmware by Qualcomm

Sm8550p Firmware by Qualcomm

Sm8635 Firmware by Qualcomm

Sm8635p Firmware by Qualcomm

Snapdragon 4 Gen 1 Mobile Platform Firmware by Qualcomm

Snapdragon 480 5g Mobile Platform Firmware by Qualcomm

Snapdragon 480\+ 5g Mobile Platform \(sm4350 Ac\) Firmware by Qualcomm

Snapdragon 690 5g Mobile Platform Firmware by Qualcomm

Snapdragon 695 5g Mobile Platform Firmware by Qualcomm

Snapdragon 765 5g Mobile Platform \(sm7250 Aa\) Firmware by Qualcomm

Snapdragon 765g 5g Mobile Platform \(sm7250 Ab\) Firmware by Qualcomm

Snapdragon 768g 5g Mobile Platform \(sm7250 Ac\) Firmware by Qualcomm

Snapdragon 778g 5g Mobile Platform Firmware by Qualcomm

Snapdragon 778g\+ 5g Mobile Platform \(sm7325 Ae\) Firmware by Qualcomm

Snapdragon 780g 5g Mobile Platform Firmware by Qualcomm

Snapdragon 782g Mobile Platform \(sm7325 Af\) Firmware by Qualcomm

Snapdragon 7c\+ Gen 3 Compute Firmware by Qualcomm

Snapdragon 8 Gen 1 Mobile Platform Firmware by Qualcomm

Snapdragon 8 Gen 1 Mobile Platform Firmware by Qualcomm

Snapdragon 8 Gen 2 Mobile Platform Firmware by Qualcomm

Snapdragon 8 Gen 2 Mobile Platform Firmware by Qualcomm

Snapdragon 8 Gen 3 Mobile Platform Firmware by Qualcomm

Snapdragon 865 5g Mobile Platform Firmware by Qualcomm

Snapdragon 865\+ 5g Mobile Platform \(sm8250 Ab\) Firmware by Qualcomm

Snapdragon 870 5g Mobile Platform \(sm8250 Ac\) Firmware by Qualcomm

Snapdragon 888 5g Mobile Platform Firmware by Qualcomm

Snapdragon 888\+ 5g Mobile Platform \(sm8350 Ac\) Firmware by Qualcomm

Snapdragon Auto 5g Modem Rf Firmware by Qualcomm

Snapdragon Auto 5g Modem Rf Gen 2 Firmware by Qualcomm

Snapdragon X55 5g Modem Rf System Firmware by Qualcomm

Snapdragon X62 5g Modem Rf System Firmware by Qualcomm

Snapdragon X65 5g Modem Rf System Firmware by Qualcomm

Snapdragon X70 Modem Rf System Firmware by Qualcomm

Snapdragon X72 5g Modem Rf System Firmware by Qualcomm

Snapdragon X75 5g Modem Rf System Firmware by Qualcomm

Video Collaboration Vc3 Platform Firmware by Qualcomm

Wcd9340 Firmware by Qualcomm

Wcd9341 Firmware by Qualcomm

Wcd9360 Firmware by Qualcomm

Wcd9370 Firmware by Qualcomm

Wcd9375 Firmware by Qualcomm

Wcd9380 Firmware by Qualcomm

Wcd9385 Firmware by Qualcomm

Wcd9390 Firmware by Qualcomm