Bug 2492807 (CVE-2026-53255)

Summary: CVE-2026-53255 kernel: Bluetooth: MGMT: validate advertising TLV before type checks
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Bluetooth Management (MGMT) component. A remote attacker could exploit this by providing specially crafted advertising data, leading to an out-of-bounds read vulnerability. This occurs because the system incorrectly validates the length of advertising data fields before performing type checks, allowing a malformed field to cause a read beyond the allocated buffer. This issue could potentially result in a denial of service or information disclosure.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-06-25 10:06:49 UTC
In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: MGMT: validate advertising TLV before type checks

tlv_data_is_valid() reads each advertising data field length from
data[i], then inspects data[i + 1] for managed EIR types before
checking that the current field still fits inside the supplied buffer.

A malformed field whose length byte is the last byte of the buffer can
therefore make the parser read one byte past the advertising data.

KASAN reported the following when a malformed MGMT_OP_ADD_ADVERTISING
request reached that path:

  BUG: KASAN: vmalloc-out-of-bounds in tlv_data_is_valid()
  Read of size 1
  Call trace:
    tlv_data_is_valid()
    add_advertising()
    hci_mgmt_cmd()
    hci_sock_sendmsg()

Move the existing element-length check before any type-octet inspection
so each non-empty element is proven to contain its type byte before the
parser looks at data[i + 1].