CVE-2025-21483: Qualcomm Apq8017 Buffer Overflow Flaw

CVE-2025-21483 Overview

CVE-2025-21483 is a critical memory corruption vulnerability affecting a wide range of Qualcomm chipsets and firmware. The vulnerability occurs when a User Equipment (UE) device receives an RTP (Real-time Transport Protocol) packet from the network during the reassembly of NALUs (Network Abstraction Layer Units). This flaw can allow remote attackers to corrupt memory on affected devices without requiring any user interaction or authentication, potentially leading to complete device compromise.

Critical Impact

This vulnerability enables remote attackers to trigger memory corruption via network-delivered RTP packets, potentially achieving arbitrary code execution on affected Qualcomm-based devices including smartphones, automotive systems, IoT devices, and wearables.

Affected Products

• Qualcomm Snapdragon 8 Gen 1/2/3 Mobile Platforms
• Qualcomm Snapdragon 865/870/888 5G Mobile Platforms
• Qualcomm FastConnect 6200/6700/6800/6900/7800 Firmware
• Qualcomm SA8155P/SA8195P/SA8255P Automotive Platforms
• Qualcomm QCM/QCS Series IoT Platforms
• Qualcomm WCN36xx/39xx/6xxx/7xxx Connectivity Chipsets

Discovery Timeline

• September 24, 2025 - CVE-2025-21483 published to NVD
• November 28, 2025 - Last updated in NVD database

Technical Details for CVE-2025-21483

Vulnerability Analysis

This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw exists in the media processing subsystem of Qualcomm chipsets, specifically within the NALU reassembly logic used for handling H.264/H.265 video streams transmitted over RTP.

When a device processes incoming RTP packets containing fragmented video NALUs, the reassembly routine fails to properly validate buffer boundaries. An attacker can craft malicious RTP packets with specially constructed NALU fragments that, when reassembled, cause the firmware to write beyond allocated memory boundaries. This can corrupt adjacent memory structures, overwrite critical data, or potentially allow arbitrary code execution.

The vulnerability is particularly concerning because RTP packets can be delivered over the network without any authentication requirements in many streaming scenarios. The attack can be triggered remotely when a vulnerable device processes malicious video content from an untrusted source.

Root Cause

The root cause is improper bounds checking during the NALU reassembly process in the media subsystem firmware. When fragmented NALUs arrive via RTP packets, the reassembly logic does not adequately verify that the combined fragment sizes fit within the allocated reassembly buffer. This allows carefully crafted fragments to trigger a buffer overflow condition during the copy operations.

Attack Vector

The attack vector is network-based, requiring the attacker to send specially crafted RTP packets to the target device. Exploitation scenarios include:

• Malicious video streaming content delivered to vulnerable applications
• Man-in-the-middle attacks injecting malicious RTP packets into video streams
• Compromised media servers serving poisoned video content
• Rogue access points delivering malicious content to connected devices

The attack requires no privileges, no user interaction, and can be executed remotely over the network. Once triggered, the memory corruption can lead to denial of service (device crash) or potentially arbitrary code execution in the context of the media processing subsystem.

The vulnerability manifests in the NALU reassembly function when processing RTP packets containing fragmented video data. When fragment sizes exceed expected boundaries during reassembly operations, memory corruption occurs. Technical details are available in the Qualcomm Security Bulletin September 2025.

Detection Methods for CVE-2025-21483

Indicators of Compromise

• Unexpected device crashes or reboots during video playback or streaming sessions
• Abnormal memory usage patterns in media processing services
• Kernel panic logs referencing media codec or video subsystem components
• Unusual RTP traffic patterns with malformed or oversized NALU fragments

Detection Strategies

• Monitor network traffic for anomalous RTP packet characteristics, particularly unusual NALU fragment sizes or sequences
• Implement firmware version checking to identify devices running vulnerable Qualcomm firmware
• Deploy network intrusion detection signatures targeting malformed RTP NALU packets
• Enable crash dump analysis on mobile and IoT devices to identify exploitation attempts

Monitoring Recommendations

• Establish baseline metrics for RTP traffic patterns in your environment to detect anomalies
• Configure logging for media subsystem crashes on Qualcomm-based devices
• Monitor for firmware update status across device fleet to ensure patching compliance
• Implement network segmentation to limit exposure of vulnerable devices to untrusted RTP sources

How to Mitigate CVE-2025-21483

Immediate Actions Required

• Apply firmware updates from Qualcomm and device OEMs as soon as they become available
• Restrict network access for vulnerable devices to trusted video streaming sources only
• Disable or limit video streaming functionality on critical devices until patches are applied
• Implement network-level filtering for malformed RTP packets where possible

Patch Information

Qualcomm has addressed this vulnerability in the September 2025 security bulletin. Device manufacturers and OEMs should integrate the updated firmware into their products. End users should apply security updates from their device manufacturers as they become available through standard update channels. Refer to the Qualcomm Security Bulletin September 2025 for detailed patch information.

Workarounds

• Avoid connecting vulnerable devices to untrusted networks or video streaming services
• Use VPN connections to protect RTP traffic from man-in-the-middle injection attacks
• Disable automatic video playback features in applications where possible
• Consider network-level deep packet inspection to filter potentially malicious RTP content

# Example: Network-level mitigation using iptables to rate-limit RTP traffic
# This can help reduce exposure but is not a complete fix
iptables -A INPUT -p udp --dport 5004:5005 -m limit --limit 1000/sec -j ACCEPT
iptables -A INPUT -p udp --dport 5004:5005 -j DROP