CVE-2026-64409

Bluetooth: btmtksdio: fix infinite loop in btmtksdio_txrx_work()

Published Jul 25, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: btmtksdio: fix infinite loop in btmtksdio_txrx_work()

Every once in a while we see a hung btmtksdio_flush() task:

INFO: task kworker/u17:0:189 blocked for more than 122 seconds.
__cancel_work_timer+0x3f4/0x460
cancel_work_sync+0x1c/0x2c
btmtksdio_flush+0x2c/0x40
hci_dev_open_sync+0x10c4/0x2190
[..]

It all boils down to incorrect time_is_before_jiffies() usage in
btmtksdio_txrx_work(). The btmtksdio_txrx_work() loop is expected
to be terminated if running for longer than 5*HZ. However the
timeout check is twisted: time_is_before_jiffies(old_jiffies + 5*HZ)
evaluates to true when old_jiffies + 5*HZ is in the past i.e. when a
timeout has occurred. Using OR with time_is_before_jiffies(txrx_timeout)
means that:
- before the 5-second timeout: the condition is `int_status || false`,
so it loops as long as there are pending interrupts.
- after the 5-second timeout: the condition becomes `int_status || true`,
which is always true.

When the loop becomes infinite btmtksdio_txrx_work() loop never
terminates and never releases the SDIO host.

Fix loop termination condition to actually enforce a 5*HZ timeout.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4720-1 linux security update
Debian DLA Debian DLA DLA-4723-1 linux-6.1 security update
Debian DLA Debian DLA DLA-4724-1 linux-6.12 new package
Ubuntu USN Ubuntu USN USN-8726-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8727-1 Linux kernel (OEM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8728-1 Linux kernel (GCP) vulnerabilities
Ubuntu USN Ubuntu USN USN-8760-1 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-8726-2 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-8726-3 Linux kernel (IBM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8800-1 Linux kernel (NVIDIA BaseOS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8760-2 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-8726-4 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8728-2 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8728-3 Linux kernel (Oracle) vulnerabilities
Ubuntu USN Ubuntu USN USN-8917-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8918-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9024-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9025-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9026-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9040-1 Linux kernel (Low Latency NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-9066-1 Linux kernel (HWE) vulnerabilities
Ubuntu USN Ubuntu USN USN-9091-1 Linux kernel (NVIDIA Tegra) vulnerabilities
History
Type Values Removed Values Added
Weaknesses CWE-400
CWE-703
Type Values Removed Values Added
Weaknesses CWE-835
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Weaknesses CWE-400
CWE-703
Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: Bluetooth: btmtksdio: fix infinite loop in btmtksdio_txrx_work() Every once in a while we see a hung btmtksdio_flush() task: INFO: task kworker/u17:0:189 blocked for more than 122 seconds. __cancel_work_timer+0x3f4/0x460 cancel_work_sync+0x1c/0x2c btmtksdio_flush+0x2c/0x40 hci_dev_open_sync+0x10c4/0x2190 [..] It all boils down to incorrect time_is_before_jiffies() usage in btmtksdio_txrx_work(). The btmtksdio_txrx_work() loop is expected to be terminated if running for longer than 5*HZ. However the timeout check is twisted: time_is_before_jiffies(old_jiffies + 5*HZ) evaluates to true when old_jiffies + 5*HZ is in the past i.e. when a timeout has occurred. Using OR with time_is_before_jiffies(txrx_timeout) means that: - before the 5-second timeout: the condition is `int_status || false`, so it loops as long as there are pending interrupts. - after the 5-second timeout: the condition becomes `int_status || true`, which is always true. When the loop becomes infinite btmtksdio_txrx_work() loop never terminates and never releases the SDIO host. Fix loop termination condition to actually enforce a 5*HZ timeout.
Title Bluetooth: btmtksdio: fix infinite loop in btmtksdio_txrx_work()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Aug 17, 2026, 4:55 AM
Reserved
Jul 19, 2026, 3:36 PM
Status
Analyzed
Published
Jul 25, 2026, 10:17 AM
Modified
Sep 4, 2026, 3:27 PM
Severity
Moderate
Public date
Jul 25, 2026, 12:00 AM