CVE-2025-21452

Q: What is the severity of CVE-2025-21452?

CVE-2025-21452 has a CVSS score of 7.5 (HIGH). This vulnerability allows attackers to cause a denial-of-service (DoS) condition on LTE networks by sending specially crafted random-access response (RAR) messages with invalid PDU lengths. It affects mobile network infrastructure equipment and devices using Qualcomm LTE modems/chipsets. The attack disrupts network availability but doesn't compromise data confidentiality or integrity.

7.5 HIGH

Denial of Service

📋 TL;DR

This vulnerability allows attackers to cause a denial-of-service (DoS) condition on LTE networks by sending specially crafted random-access response (RAR) messages with invalid PDU lengths. It affects mobile network infrastructure equipment and devices using Qualcomm LTE modems/chipsets. The attack disrupts network availability but doesn't compromise data confidentiality or integrity.

💻 Affected Systems

Products:

Qualcomm LTE modems
Mobile devices with Qualcomm chipsets
LTE network infrastructure equipment

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

Operating Systems: Embedded/baseband OS on affected chipsets

Default Config Vulnerable: ⚠️ Yes

Notes: Affects systems processing LTE RAR messages; exact product list requires checking Qualcomm's advisory.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Sustained DoS affecting multiple base stations or network segments, disrupting mobile service for large geographic areas.

🟠

Likely Case

Temporary service disruption affecting individual cells or devices, causing dropped connections and degraded network performance.

🟢

If Mitigated

Minimal impact with proper network segmentation and monitoring; isolated incidents quickly detected and contained.

🌐 Internet-Facing: MEDIUM - LTE networks are accessible via radio interface, but exploitation requires specialized equipment and proximity.

🏢 Internal Only: LOW - This is primarily a radio interface vulnerability, not typically exploitable from internal corporate networks.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires LTE protocol knowledge and radio transmission capability; no authentication needed as it targets network signaling.

🛠️ 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 products. 2. Obtain updated firmware from device manufacturer or carrier. 3. Apply firmware update following vendor instructions. 4. Reboot affected devices/systems.

🔧 Temporary Workarounds

Network monitoring and filtering

all

Implement network monitoring to detect anomalous RAR traffic and filter suspicious messages

🧯 If You Can't Patch

Implement network segmentation to limit blast radius of DoS attacks
Deploy redundant systems with failover capabilities to maintain service during attacks

🔍 How to Verify

Check if Vulnerable:

Check device firmware version against Qualcomm's patched versions list in the August 2025 bulletin

Check Version:

Device-specific; typically via AT commands or device management interfaces (e.g., AT+CGMR for modems)

Verify Fix Applied:

Verify firmware version matches or exceeds patched version specified by Qualcomm

📡 Detection & Monitoring

Log Indicators:

Unexpected baseband resets
Increased RAR processing errors
Abnormal LTE signaling messages

Network Indicators:

Spike in RAR messages with unusual lengths
Increased radio link failures
Abnormal cell reselection patterns

SIEM Query:

Example: 'source="lte_logs" AND (message="RAR length error" OR message="PDU validation failed")'

📊 Metadata

CVE ID: CVE-2025-21452

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-617

EPSS Score: 0.02% exploit probability (5.2th 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

Fsm10055 Firmware by Qualcomm

Qca6174a Firmware by Qualcomm

Qca6391 Firmware by Qualcomm

Qca6421 Firmware by Qualcomm

Qca6426 Firmware by Qualcomm

Qca6431 Firmware by Qualcomm

Qca6436 Firmware by Qualcomm

Qca6574a Firmware by Qualcomm

Qca6574au Firmware by Qualcomm

Qca6595au Firmware by Qualcomm

Qca6696 Firmware by Qualcomm

Qca6698aq Firmware by Qualcomm

Qca8337 Firmware by Qualcomm

Qcm5430 Firmware by Qualcomm

Qcm6490 Firmware by Qualcomm

Qcs5430 Firmware by Qualcomm

Qcs6490 Firmware by Qualcomm

Qep8111 Firmware by Qualcomm

Sd855 Firmware by Qualcomm

Sd865 5g Firmware by Qualcomm

Sdx55 Firmware by Qualcomm

Sdx57m Firmware by Qualcomm

Sm6370 Firmware by Qualcomm

Sm6650 Firmware by Qualcomm

Sm7250p Firmware by Qualcomm

Sm7325p Firmware by Qualcomm

Sm7635 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 855 Mobile Platform Firmware by Qualcomm

Snapdragon 855\+\/860 Mobile Platform \(sm8150 Ac\) 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 X35 5g Modem Rf System Firmware by Qualcomm

Snapdragon X55 5g Modem Rf System Firmware by Qualcomm

Snapdragon Xr2 5g Platform Firmware by Qualcomm

Sxr2130 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

Wcd9378 Firmware by Qualcomm

Wcd9380 Firmware by Qualcomm

Wcd9385 Firmware by Qualcomm

Wcd9395 Firmware by Qualcomm

Wcn3988 Firmware by Qualcomm

Wcn6450 Firmware by Qualcomm

Wcn6650 Firmware by Qualcomm

Wcn6740 Firmware by Qualcomm

Wcn6755 Firmware by Qualcomm

Wcn7861 Firmware by Qualcomm

Wcn7881 Firmware by Qualcomm

Wsa8810 Firmware by Qualcomm

Wsa8815 Firmware by Qualcomm