CVE-2026-53209

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.

CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0014

Probability of exploitation

0.04%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/02f50e8bb69f9b22516163a09922f5537d3b12d1 https://git.kernel.org/stable/c/10b0e832cc05d7aef4b92bed912cbd4a395d0862 https://git.kernel.org/stable/c/1338ee049a8910ba6c9cee963920e978e6893c7d https://git.kernel.org/stable/c/5c65b96b549ea2dcfde497436bf9e048deb87758 https://git.kernel.org/stable/c/cdd8bbdbee763fdf5bf343e6f7d4e79347739f62 https://git.kernel.org/stable/c/dafc9f57140e66a10945127aa7433c3d715dc253

Frequently Asked Questions

What is CVE-2026-53209? +

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. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-53209? +

CVE-2026-53209 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0014, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-53209? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.