CVE-2026-2411: Zephyr's Bluetooth host declares a GATT characteristic as two consecutive attributes: a Characteristic Declara

Q: How do I fix CVE-2026-2411?

zephyr: upgrade to 4.5.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-2411 being exploited?

CVE-2026-2411 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-2411 affect?

CVE-2026-2411 affects zephyr. Severity is medium (CVSS 6.5). Zephyr's Bluetooth host declares a GATT characteristic as two consecutive attributes: a Characteristic Declaration whose permission is hard-coded to BT_GATT_PERM_READ, and a Characteristic Value attribute that carries the application-specif

Q: How urgent is CVE-2026-2411?

Priority 30/100. Public exploit reference

Routine

MEDIUM 6.5UPGRADE

CVE-2026-2411 is a medium-severity flaw (CVSS 6.5) affecting zephyr. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Zephyr's Bluetooth host declares a GATT characteristic as two consecutive attributes: a Characteristic Declaration whose permission is hard-coded to BT_GATT_PERM_READ, and a Characteristic Value attribute that carries the application-specified security permissions (e.g. BT_GATT_PERM_READ_ENCRYPT / READ_AUTHEN / READ_LESC). The public notify and indicate APIs explicitly accept either attribute, and passing the declaration is the documented, common

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Adjacent network
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 92%)
CISA exploited list	No
Weakness	CWE-863
Published	2026-08-01
Last modified	2026-10-23

Publisher (CNA): Zephyr Project · Vendor: zephyrproject

Am I affected?

Timeline

2026-08-01 13:16 UTCPublished CVE record published
2026-10-23 23:10 UTCUpdated Record last modified

zephyrproject zephyr UPGRADE

Affected: >= 2.6.0 and < 4.5.0

Fixed in: 4.5.0

Safe to downgrade to: a release before 2.6.0

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.

Quick answers

How do I fix CVE-2026-2411?

zephyr: upgrade to 4.5.0. Exact commands for each OS are on this page.

Is CVE-2026-2411 being exploited?

CVE-2026-2411 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-2411 affect?

CVE-2026-2411 affects zephyr. Severity is medium (CVSS 6.5). Zephyr's Bluetooth host declares a GATT characteristic as two consecutive attributes: a Characteristic Declaration whose permission is hard-coded to BT_GATT_PERM_READ, and a Characteristic Value attribute that carries the application-specif

How urgent is CVE-2026-2411?

Priority 30/100. Public exploit reference

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References

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