CVE-2026-10651
bt_sdp_parse_attribute() in subsys/bluetooth/host/classic/sdp.c validated only that the SDP record buffer held the type-marker byte plus the 2-byte attribute ID (a check of buf->len < 3) but then read a fourth byte, the data-element descriptor (type), via net_buf_simple_pull_u8(). Because net_buf_simple_pull_u8() dereferences buf->data[0] before its only bounds guard (an __ASSERT_NO_MSG that compiles out when CONFIG_ASSERT is disabled, the production default), a record of exactly three bytes (0x09 followed by a 2-byte attribute ID) causes a one-byte read past the end of the logical buffer. The parser is reachable from inbound, remote-controlled data: a Bluetooth BR/EDR peer acting as an SDP server returns discovery-response records that are stored verbatim in the client receive buffer and parsed via the public bt_sdp_get_attr()/bt_sdp_has_attr()/bt_sdp_record_parse() helpers. The over-read is bounded to a single byte that is used only as an internal length selector and is never leaked to the attacker; subsequent length checks then reject the malformed record. Realistic impact is therefore limited to an edge-case denial of service (a fault only if the record ends exactly at a mapped
Weakness
bt_sdp_parse_attribute() in subsys/bluetooth/host/classic/sdp.c validated only that the SDP record buffer held the type-marker byte plus the 2-byte attribute ID (a check of buf->len < 3) but then read a fourth byte, the data-element descriptor (type), via net_buf_simple_pull_u8(). Because net_buf_simple_pull_u8() dereferences buf->data[0] before its only bounds guard (an __ASSERT_NO_MSG that compiles out when CONFIG_ASSERT is disabled, the production default), a record of exactly three bytes (0x09 followed by a 2-byte attribute ID) causes a one-byte read past the end of the logical buffer. The parser is reachable from inbound, remote-controlled data: a Bluetooth BR/EDR peer acting as an SDP server returns discovery-response records that are stored verbatim in the client receive buffer and parsed via the public bt_sdp_get_attr()/bt_sdp_has_attr()/bt_sdp_record_parse() helpers. The over-read is bounded to a single byte that is used only as an internal length selector and is never leaked to the attacker; subsequent length checks then reject the malformed record. Realistic impact is therefore limited to an edge-case denial of service (a fault only if the record ends exactly at a mapped
Affected products
- zephyrproject zephyr
References
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