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CVE-2026-10685: The Zephyr Bluetooth GATT client CCC-write response handler gatt_write_ccc_rsp() in subsys/bluetooth/host/gatt

37
Routine
HIGH 7.6UPGRADE

CVE-2026-10685 is a high-severity flaw (CVSS 7.6) affecting zephyr. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The Zephyr Bluetooth GATT client CCC-write response handler gatt_write_ccc_rsp() in subsys/bluetooth/host/gatt.c invoked the application's params->subscribe() callback after it had already called params->notify(conn, params, NULL, 0). Per the public GATT API, a notify callback with NULL data is the documented signal that the subscription has terminated and the bt_gatt_subscribe_params struct may be freed or reused by the application; calling sub

Why this priority

  • High severity
  • Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score7.6 (High)
Attack vectorAdjacent network
Attack complexityLow
Privileges neededNone
User interactionNone
EPSS exploit chance0.3% (top 78%)
CISA exploited listNo
WeaknessCWE-416
Published2026-07-31
Last modified2026-10-23
Publisher (CNA): Zephyr Project · Vendor: zephyrproject

Am I affected?

Timeline

zephyrproject zephyr UPGRADE
Affected: >= 2.4.0 and < 4.5.0
Fixed in: 4.5.0
Safe to downgrade to: a release before 2.4.0
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Related CVEs

References

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