CVE-2025-21427: Qualcomm Sm6250 Information Disclosure Flaw

CVE-2025-21427 Overview

CVE-2025-21427 is an information disclosure vulnerability affecting Qualcomm chipset firmware that occurs during Real-Time Transport Protocol (RTP) packet payload decoding. When a User Equipment (UE) receives an RTP packet from the network, improper handling of the payload data can lead to the exposure of sensitive information. This vulnerability represents a significant risk to mobile devices, automotive platforms, IoT devices, and other systems utilizing affected Qualcomm processors.

Critical Impact

This information disclosure vulnerability can be exploited remotely over the network without authentication, potentially exposing sensitive memory contents from affected devices during RTP media streaming sessions.

Affected Products

• Qualcomm Snapdragon 8 Gen 1/2/3 Mobile Platforms (Firmware)
• Qualcomm Snapdragon 888/888+ 5G Mobile Platforms (Firmware)
• Qualcomm Snapdragon 865/865+ 5G Mobile Platforms (Firmware)
• Qualcomm Snapdragon 855/855+ Mobile Platforms (Firmware)
• Qualcomm Snapdragon 845 Mobile Platform (Firmware)
• Qualcomm Snapdragon 835 Mobile Platform (Firmware)
• Qualcomm Snapdragon 778G/780G 5G Mobile Platforms (Firmware)
• Qualcomm SA8155P/SA8195P Automotive Platforms (Firmware)
• Qualcomm FastConnect 6700/6800/6900/7800 (Firmware)
• Qualcomm SDX55 5G Modem (Firmware)

Discovery Timeline

• July 8, 2025 - CVE-2025-21427 published to NVD
• February 11, 2026 - Last updated in NVD database

Technical Details for CVE-2025-21427

Vulnerability Analysis

This vulnerability is classified under CWE-126 (Buffer Over-read) and CWE-125 (Out-of-Bounds Read). The flaw exists in the RTP packet payload decoding mechanism within Qualcomm chipset firmware. When processing incoming RTP packets from the network, the decoder fails to properly validate the boundaries of the payload data, leading to an out-of-bounds read condition.

RTP is a standard protocol used for delivering audio and video over IP networks, commonly employed in VoIP calls, video conferencing, and media streaming applications. The vulnerability is particularly concerning because RTP traffic is a fundamental component of modern mobile communications, including Voice over LTE (VoLTE) and Voice over Wi-Fi (VoWiFi) services.

The attack can be executed remotely over the network without requiring any user interaction or authentication, making it highly accessible to potential attackers. Successful exploitation could result in the disclosure of sensitive memory contents from the device, though the vulnerability does not appear to enable arbitrary code execution or complete system compromise.

Root Cause

The root cause of this vulnerability is improper bounds checking during RTP packet payload decoding. When the UE receives an RTP packet, the decoding routine reads data based on length fields or indicators within the packet without adequately validating that these values correspond to actual allocated buffer sizes. This allows a malformed RTP packet with manipulated length fields to trigger reads beyond the intended buffer boundaries.

The buffer over-read condition (CWE-126) occurs because the code assumes the packet payload conforms to expected size constraints without verification. This type of vulnerability is common in network protocol implementations where performance optimizations may lead developers to skip exhaustive boundary validation.

Attack Vector

The attack vector for CVE-2025-21427 is network-based, meaning an attacker must be positioned to send malicious RTP packets to the target device. Potential attack scenarios include:

The attacker sends specially crafted RTP packets to the target device during an active media session. These packets contain manipulated payload length indicators that cause the decoder to read memory beyond the allocated buffer boundaries.

During VoLTE or VoWiFi calls, an attacker positioned as a network intermediary could inject malicious RTP packets into the media stream. The attack requires low complexity as it does not need authentication or special privileges.

The vulnerability affects a wide range of Qualcomm chipsets spanning mobile, automotive, IoT, and computing platforms, significantly expanding the potential attack surface across billions of deployed devices.

Detection Methods for CVE-2025-21427

Indicators of Compromise

• Anomalous RTP packet traffic with malformed or oversized payload length fields targeting affected devices
• Unusual memory access patterns or crashes in the modem or media processing subsystems
• Unexpected data in network traffic responses that may indicate leaked memory contents
• System instability during VoLTE, VoWiFi, or other RTP-based media sessions

Detection Strategies

• Monitor network traffic for RTP packets with suspicious payload length indicators that exceed expected values
• Implement deep packet inspection rules to identify malformed RTP packets targeting mobile devices
• Deploy network-based intrusion detection signatures for known RTP exploitation patterns
• Analyze modem crash logs for evidence of out-of-bounds read conditions during RTP processing

Monitoring Recommendations

• Enable logging on network infrastructure components to capture RTP traffic anomalies
• Monitor devices for unexplained modem restarts or media subsystem failures that could indicate exploitation attempts
• Implement anomaly detection for unusual RTP session characteristics or unexpected packet patterns
• Establish baseline metrics for normal RTP traffic to identify deviations that may indicate attack activity

How to Mitigate CVE-2025-21427

Immediate Actions Required

• Apply firmware updates from Qualcomm and device OEMs as they become available through vendor security bulletins
• Review the Qualcomm July 2025 Security Bulletin for specific patch information and affected product details
• Prioritize patching for devices with high exposure to untrusted networks or those processing sensitive communications
• Consider network-level mitigations such as RTP traffic filtering where feasible pending firmware updates

Patch Information

Qualcomm has addressed this vulnerability in their July 2025 security bulletin. Device manufacturers (OEMs) must integrate these patches into their firmware updates and distribute them to end users. The patching timeline varies by manufacturer and device model.

Users should check for system updates from their device manufacturers and mobile carriers. For automotive and IoT deployments, coordinate with system integrators and vendors to ensure timely patch deployment across affected infrastructure.

Enterprise administrators managing device fleets should prioritize firmware updates for affected Qualcomm-based devices, particularly those used in environments where sensitive communications occur.

Workarounds

• Limit exposure to untrusted networks where possible to reduce the attack surface for network-based exploitation
• Consider implementing network segmentation to isolate devices with affected chipsets from potentially hostile network traffic
• Monitor for vendor security bulletins and apply firmware updates promptly when available
• For enterprise deployments, consider implementing additional network-level filtering for RTP traffic from untrusted sources

# Check device chipset information on Android devices
adb shell getprop ro.board.platform
adb shell getprop ro.hardware

# Review current firmware/build version
adb shell getprop ro.build.version.security_patch
adb shell getprop ro.build.fingerprint