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High · 7.1 CVE-2026-10651 EUVD-2026-38409

Out-of-bounds read in Bluetooth Classic SDP attribute parsing (`bt_sdp_parse_attribute`)

Published Jun 22, 2026 · Updated Nov 4, 2026 · Assigned by zephyr

Description

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-memory boundary, or a deterministic assert panic when CONFIG_ASSERT=y). Affects Zephyr v4.3.0 and v4.4.0; fixed by adding sizeof(type) to the length check.

Affected products

VendorProductAffectedFixed
zephyrproject zephyr 4.3.0 – < 4.6.0 4.6.0

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Ubuntu 26.10 zephyr No fix yet —
Ubuntu 26.04 LTS zephyr No fix yet —
Ubuntu 25.10 zephyr No fix yet —
Ubuntu 24.04 LTS zephyr No fix yet —
Ubuntu 22.04 LTS zephyr No fix yet —
Show 3 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 20.04 LTS zephyr No fix yet —
Ubuntu 18.04 LTS zephyr No fix yet —
Ubuntu 16.04 LTS zephyr No fix yet —

References