CVE-2026-53209
Published: June 25, 2026· Updated: Jun 30, 2026
Official Description
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_sync: reject oversized Broadcast Announcement prepend
Existing advertising instances can already hold the maximum extended
advertising payload. When hci_adv_bcast_annoucement() prepends the
Broadcast Announcement service data to that payload, the combined data
may no longer fit in the temporary buffer used to rebuild the
advertising data.
Reject that case before copying the existing payload and report the
failure through the device log. This keeps the existing advertising
data intact and avoids overrunning the temporary buffer.
Technical Analysis
CVE-2026-53209 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 7.8.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
All References (6)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-53209 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts