Heap Out-of-Bounds Read in BlueZ SBC Library

Executive Summary

This is a heap out-of-bounds read vulnerability in the SBC (Subband Codec) library affecting versions 1.0 through 2.0. An off-by-one error in the bit-reader bound check allows the cumulative bit position to reach exactly the buffer length, causing a one-byte heap read past the end of the input buffer. This flaw was introduced in 2011 and affects applications like PulseAudio, PipeWire, and GStreamer that use the vulnerable decode path.

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Detection Guidance

To detect this vulnerability, check if your system uses a vulnerable version of the SBC library (versions 1.0 through 2.0). Inspect the library version with commands like 'dpkg -l | grep sbc' on Debian-based systems or 'rpm -qa | grep sbc' on RPM-based systems. If vulnerable, monitor for crashes or memory corruption during Bluetooth audio streaming.

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Impact Analysis

An attacker could exploit this by sending a crafted Bluetooth audio frame to read a single byte of adjacent heap memory. Since SBC is the mandatory A2DP codec for Bluetooth audio, any device decoding Bluetooth audio is potentially affected. The impact includes potential information leakage from memory.

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Compliance Impact

This vulnerability does not directly impact compliance with GDPR, HIPAA, or similar standards. It involves a heap out-of-bounds read in Bluetooth audio decoding, which could potentially expose small amounts of adjacent memory but does not inherently lead to unauthorized data access or processing of sensitive information.

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Mitigation Strategies

Update the SBC library to a patched version if available. If using PulseAudio, PipeWire, or other affected software, update those packages as they may bundle a vulnerable libsbc. Disable Bluetooth audio streaming temporarily if no patch is available. Monitor vendor advisories for updates.

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