CVE-2026-16473: BlueZ SBC Codec Use-After-Free Vulnerability

CVE-2026-16473 Overview

CVE-2026-16473 is an off-by-one flaw in the BlueZ sbc library, which implements the Subband Coding (SBC) audio codec used by Bluetooth A2DP audio streaming. The SBC frame decoder mishandles a boundary condition, causing a one-byte heap out-of-bounds read when processing a crafted audio payload. An attacker within Bluetooth range who can stream audio to a target device can trigger the read and disclose a single byte of adjacent heap memory. The issue is tracked under [CWE-125: Out-of-bounds Read] and is exposed through the standard Bluetooth audio pipeline.

Critical Impact
An adjacent attacker streaming Bluetooth audio can read one byte of adjacent heap memory in any process linking the vulnerable sbc library.

Affected Products

BlueZ sbc library (SBC codec) as distributed via the upstream Kernel Git Repository
Linux distributions shipping the BlueZ sbc codec, per the Red Hat CVE Advisory
Applications and daemons that decode SBC audio frames using the vulnerable library

Discovery Timeline

2026-07-22 - CVE-2026-16473 published to NVD
2026-07-22 - Last updated in NVD database

Technical Details for CVE-2026-16473

Vulnerability Analysis

The sbc library decodes SBC-encoded audio frames delivered over Bluetooth A2DP. The frame decoder performs bounds arithmetic that is off by one when validating the extent of a decoded payload buffer. On a specifically crafted frame, the decoder reads one byte past the end of the allocated heap buffer. The read does not corrupt memory, but it can leak the value of the adjacent byte through decoder side effects or downstream audio processing.

Exploitation requires network adjacency because SBC frames are delivered over an established Bluetooth audio link. No user interaction or authentication on the target application is required beyond an active audio session. The result is a limited confidentiality impact with no direct effect on integrity or availability.

Root Cause

The root cause is an incorrect boundary check in the SBC frame decoding routine. The length calculation permits a loop or index to advance one position beyond the valid payload extent, producing a heap out-of-bounds read of a single byte. See the Red Hat Bug Report for the underlying analysis.

Attack Vector

An attacker within Bluetooth range establishes or hijacks an A2DP audio stream to the target and delivers a malformed SBC frame. The vulnerable decoder processes the frame and reads one byte past the end of the heap allocation holding the frame payload. Repeated frames allow an attacker to sample bytes across multiple decoder invocations. The disclosure is narrow but repeatable while the audio session is active.

No verified proof-of-concept code is published. Refer to the Red Hat CVE Advisory for further technical detail.

Detection Methods for CVE-2026-16473

Indicators of Compromise

Unexpected pairing attempts or A2DP audio connections from unknown Bluetooth peers on user endpoints or IoT devices.
Crash reports, sanitizer alerts, or AddressSanitizer heap-buffer-overflow read events originating from sbc_decode or related symbols in the sbc library.
Anomalous audio session activity from PulseAudio, PipeWire, or bluetoothd when no user-initiated pairing occurred.

Detection Strategies

Enable and monitor kernel and userspace crash telemetry for processes linking libsbc, including PulseAudio, PipeWire, and bluetoothd.
Build test images with AddressSanitizer for fleet validation to surface the one-byte out-of-bounds read against known malformed frames.
Inventory hosts running vulnerable sbc package versions using standard software composition analysis against Linux package data.

Monitoring Recommendations

Log Bluetooth pairing and A2DP connection events centrally and alert on connections from unrecognized device addresses.
Restrict Bluetooth adapter usage on servers and workstations where audio streaming is not required.
Track distribution security advisories referenced in the Red Hat CVE Advisory for updated sbc packages.

How to Mitigate CVE-2026-16473

Immediate Actions Required

Update the sbc package to the fixed version supplied by your Linux distribution once available.
Disable Bluetooth on systems that do not require audio streaming, particularly servers, kiosks, and unattended endpoints.
Unpair and remove untrusted Bluetooth peers and set adapters to non-discoverable mode.

Patch Information

Patches are being coordinated through the upstream project at the Kernel Git Repository and distributed via vendor advisories. Track the Red Hat CVE Advisory and the Red Hat Bug Report for fixed package versions and errata identifiers.

Workarounds

Stop and mask bluetooth.service on systems that do not need Bluetooth audio functionality.
Configure Bluetooth adapters as non-discoverable and require explicit user approval for new pairings.
Limit physical proximity by disabling Bluetooth on portable devices when operating in untrusted environments.

bash

# Disable Bluetooth service on systems that do not require it
sudo systemctl stop bluetooth.service
sudo systemctl disable bluetooth.service
sudo systemctl mask bluetooth.service

# Verify installed sbc package version and update once a fixed release is available
rpm -q sbc            # Red Hat / Fedora based distributions
dpkg -l | grep libsbc # Debian / Ubuntu based distributions
sudo dnf update sbc   # or: sudo apt update && sudo apt install --only-upgrade libsbc1