CVE-2025-21448: Qualcomm Qcn9070 Firmware DOS Vulnerability

CVE-2025-21448 Overview

CVE-2025-21448 is a transient denial-of-service (DoS) vulnerability affecting a broad range of Qualcomm chipsets and firmware. The flaw resides in the WLAN firmware logic responsible for parsing the Service Set Identifier (SSID) inside 802.11 action frames. An attacker within wireless range can transmit a malformed action frame to trigger the condition, disrupting Wi-Fi connectivity on the target device. The issue is classified under CWE-126: Buffer Over-read and impacts Snapdragon mobile, compute, automotive, IoT, and networking platforms.

Critical Impact
A remote, unauthenticated attacker can induce a transient denial of service on affected Qualcomm WLAN-enabled devices by transmitting crafted 802.11 action frames containing a malformed SSID element.

Affected Products

Qualcomm Snapdragon mobile platforms (Snapdragon 8 Gen 1/2/3, 865/870/888, 778G, 780G series)
Qualcomm FastConnect, QCA, QCN, IPQ, and WCN Wi-Fi/connectivity chipsets
Qualcomm automotive (SA8155P, SA8255P, SA8775P), compute (SC8180X, SC8380XP), and IoT platforms (QCS, QCM series)

Discovery Timeline

2025-04-07 - CVE CVE-2025-21448 published to NVD
2025-04-07 - Qualcomm publishes the April 2025 Security Bulletin
2025-10-06 - Last updated in NVD database

Technical Details for CVE-2025-21448

Vulnerability Analysis

The vulnerability resides in the WLAN firmware code path that processes 802.11 management frames, specifically action frames carrying an SSID information element. When the firmware parses the SSID field, it fails to enforce correct bounds against the length advertised in the frame header. Processing a malformed SSID causes the firmware to read outside the intended buffer, producing a fault that halts the WLAN subsystem. Recovery requires a reset of the Wi-Fi stack, producing the transient denial-of-service condition described by Qualcomm.

Because the attack target is the WLAN baseband firmware, exploitation does not require authentication, user interaction, or association with the access point. Any attacker within radio range can transmit the crafted frame to any device exposing the affected Wi-Fi interface.

Root Cause

The root cause is improper validation of the SSID length field embedded in action frames. The parser trusts the attacker-supplied length value when copying or iterating over the SSID buffer. This CWE-126: Buffer Over-read leads to reads past the allocated frame buffer and a subsequent firmware fault.

Attack Vector

Exploitation occurs over the wireless adjacent network. The attacker constructs an 802.11 action frame containing a malformed SSID information element and broadcasts it within range of the target. The target device's WLAN firmware ingests the frame during normal frame processing and triggers the over-read. The result is loss of wireless connectivity until the WLAN subsystem reinitializes. No code execution or data disclosure is reported as part of this CVE.

The vulnerability cannot be exploited remotely over the internet, but in dense environments, vehicles, or enterprise wireless deployments, an attacker with a standard Wi-Fi adapter can disrupt service for nearby devices.

Detection Methods for CVE-2025-21448

Indicators of Compromise

Unexpected WLAN subsystem crashes, restarts, or wlan driver kernel log entries on Qualcomm-based mobile, IoT, or networking devices.
Repeated loss of Wi-Fi association from multiple nearby devices simultaneously, indicating a broadcast-range attack source.
Anomalous 802.11 action frames with malformed or oversized SSID information elements observed in wireless packet captures.

Detection Strategies

Capture 802.11 management traffic with monitor-mode tools such as tcpdump or Wireshark and inspect action frames for SSID information elements whose declared length exceeds the frame payload.
Correlate device-side WLAN firmware crash telemetry with wireless intrusion detection system (WIDS) alerts to identify localized RF attacks.
Monitor mobile device management (MDM) and endpoint telemetry for repeated Wi-Fi disconnection events on patched-out-of-date Qualcomm devices.

Monitoring Recommendations

Deploy WIDS or wireless sensors in high-value areas (executive floors, vehicle fleets, OT environments) to flag malformed management frames.
Forward WLAN firmware crash logs from managed endpoints to a central log platform for correlation with proximity-based events.
Track Qualcomm firmware versions across the fleet and alert on devices running pre-April-2025 baseband or WLAN firmware revisions.

How to Mitigate CVE-2025-21448

Immediate Actions Required

Apply the firmware updates referenced in the Qualcomm April 2025 Security Bulletin through your OEM as soon as they are available.
Inventory all Qualcomm-based devices in scope (mobile handsets, laptops, automotive head units, IoT gateways, Wi-Fi access points) and map them to vendor patch availability.
Prioritize patching for devices operating in high-risk RF environments such as public venues, conference facilities, and connected vehicles.

Patch Information

Qualcomm has addressed CVE-2025-21448 in the firmware updates published in the April 2025 Security Bulletin. Patches are distributed through device OEMs and platform vendors. Customers should consult their OEM's update channel to obtain the corresponding baseband, WLAN, and platform firmware revisions.

Workarounds

Disable Wi-Fi on affected devices when operating in untrusted RF environments until OEM firmware updates are deployed.
Restrict use of vulnerable devices to controlled wireless environments protected by WIDS and 802.11w (Management Frame Protection) where supported.
Segment IoT and automotive Qualcomm-based devices on dedicated wireless networks with reduced exposure to untrusted clients.

bash

# Example: verify Qualcomm WLAN firmware version on a Linux-based device
# and confirm it matches the OEM-provided post-April-2025 build
dmesg | grep -i "wlan\|qcom\|firmware"
iw dev wlan0 info
ethtool -i wlan0 | grep -i firmware