CVE-2026-63944: In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: fix UAF in hci_le_cr

Q: How do I fix CVE-2026-63944?

linux kernel: upgrade to 6.6.143, 6.12.93, 6.18.35, 7.0.12. Exact commands for each OS are on this page.

Q: Is CVE-2026-63944 being exploited?

CVE-2026-63944 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-2026-63944 affect?

CVE-2026-63944 affects linux kernel. Severity is high (CVSS 8.8). In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync hci_le_create_cis_sync() dereferences conn->conn_timeout after releasing both rcu_read_lock() and hci_dev_lock(hdev

This month

HIGH 8.8WATCHLISTUPGRADE

CVE-2026-63944 is a high-severity flaw (CVSS 8.8) affecting linux kernel. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync hci_le_create_cis_sync() dereferences conn->conn_timeout after releasing both rcu_read_lock() and hci_dev_lock(hdev). The conn pointer was obtained from an RCU-protected iteration over hdev->conn_hash.list and is not valid once these locks are dropped. A concurrent disconnect can free the hci_conn between the unlock and t

Why this priority

High severity
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Adjacent network
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 73%)
CISA exploited list	No
Weakness	CWE-416
Published	2026-07-19
Last modified	2026-10-26

Publisher (CNA): kernel.org · Vendor: linux

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-19 16:17 UTCPublished CVE record published
2026-10-26 13:33 UTCUpdated Record last modified

linux linux kernel UPGRADE

Affected: >= 6.4 and < 6.6.143 · >= 6.7 and < 6.12.93 · >= 6.13 and < 6.18.35 · >= 6.19 and < 7.0.12 · 7.1 rc1 · 7.1 rc2 · 7.1 rc3 · 7.1 rc4

Fixed in: 6.6.143, 6.12.93, 6.18.35, 7.0.12

Safe to downgrade to: no unaffected older release

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-2026-63944?

linux kernel: upgrade to 6.6.143, 6.12.93, 6.18.35, 7.0.12. Exact commands for each OS are on this page.

Is CVE-2026-63944 being exploited?

CVE-2026-63944 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-2026-63944 affect?

CVE-2026-63944 affects linux kernel. Severity is high (CVSS 8.8). In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync hci_le_create_cis_sync() dereferences conn->conn_timeout after releasing both rcu_read_lock() and hci_dev_lock(hdev

How urgent is CVE-2026-63944?

Priority 42/100. High severity; On your watchlist

Software pages

Linux kernel vulnerabilities · Bluetooth vulnerabilities

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References

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