CVE-2022-50773 - Vulnerability Details

In the Linux kernel, the following vulnerability has been resolved:

ALSA: mts64: fix possible null-ptr-defer in snd_mts64_interrupt

I got a null-ptr-defer error report when I do the following tests
on the qemu platform:

make defconfig and CONFIG_PARPORT=m, CONFIG_PARPORT_PC=m,
CONFIG_SND_MTS64=m

Then making test scripts:
cat>test_mod1.sh<<EOF
modprobe snd-mts64
modprobe snd-mts64
EOF

Executing the script, perhaps several times, we will get a null-ptr-defer
report, as follow:

syzkaller:~# ./test_mod.sh
snd_mts64: probe of snd_mts64.0 failed with error -5
modprobe: ERROR: could not insert 'snd_mts64': No such device
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 0 P4D 0
Oops: 0002 [#1] PREEMPT SMP PTI
CPU: 0 PID: 205 Comm: modprobe Not tainted 6.1.0-rc8-00588-g76dcd734eca2 #6
Call Trace:
<IRQ>
snd_mts64_interrupt+0x24/0xa0 [snd_mts64]
parport_irq_handler+0x37/0x50 [parport]
__handle_irq_event_percpu+0x39/0x190
handle_irq_event_percpu+0xa/0x30
handle_irq_event+0x2f/0x50
handle_edge_irq+0x99/0x1b0
__common_interrupt+0x5d/0x100
common_interrupt+0xa0/0xc0
</IRQ>
<TASK>
asm_common_interrupt+0x22/0x40
RIP: 0010:_raw_write_unlock_irqrestore+0x11/0x30
parport_claim+0xbd/0x230 [parport]
snd_mts64_probe+0x14a/0x465 [snd_mts64]
platform_probe+0x3f/0xa0
really_probe+0x129/0x2c0
__driver_probe_device+0x6d/0xc0
driver_probe_device+0x1a/0xa0
__device_attach_driver+0x7a/0xb0
bus_for_each_drv+0x62/0xb0
__device_attach+0xe4/0x180
bus_probe_device+0x82/0xa0
device_add+0x550/0x920
platform_device_add+0x106/0x220
snd_mts64_attach+0x2e/0x80 [snd_mts64]
port_check+0x14/0x20 [parport]
bus_for_each_dev+0x6e/0xc0
__parport_register_driver+0x7c/0xb0 [parport]
snd_mts64_module_init+0x31/0x1000 [snd_mts64]
do_one_initcall+0x3c/0x1f0
do_init_module+0x46/0x1c6
load_module+0x1d8d/0x1e10
__do_sys_finit_module+0xa2/0xf0
do_syscall_64+0x37/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
</TASK>
Kernel panic - not syncing: Fatal exception in interrupt
Rebooting in 1 seconds..

The mts wa not initialized during interrupt, we add check for
mts to fix this bug.

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00033.

Key SSVC decision points have not yet been added.

Vendors	Products
Linux Subscribe	Linux Kernel Subscribe

No data.

Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References

Link	Providers
https://git.kernel.org/stable/c/0649129359219ce6ff380ec401f87308485c6ae3
https://git.kernel.org/stable/c/06ec592389f2be3199779ab823c4323dcfd2121f
https://git.kernel.org/stable/c/1a763c748acd5540ccc43306c57c9c6c5fb60884
https://git.kernel.org/stable/c/250eed7b9994d79f9c409f954dbd08e88f5afd83
https://git.kernel.org/stable/c/7e91667db38abb056da5a496d40fbd044c66bed2
https://git.kernel.org/stable/c/b471fe61da523a15e4cb60fa81f5a2377e4bad98
https://git.kernel.org/stable/c/c7e9624d90bf20f1eed6b228949396d614b94020
https://git.kernel.org/stable/c/cba633b24a98d957e8190ef8bc4d4cdb4f6e9313
https://git.kernel.org/stable/c/cf2ea3c86ad90d63d1c572b43e1ca9276b0357ad
https://lore.kernel.org/linux-cve-announce/2025122459-CVE-2022-50773-b946@gregkh/T
https://nvd.nist.gov/vuln/detail/CVE-2022-50773
https://www.cve.org/CVERecord?id=CVE-2022-50773

History

Thu, 25 Dec 2025 00:15:00 +0000

Type	Values Removed	Values Added
References		https://lore.kernel.org/linux-cve-announce/2025122459-CVE-2022-50773-b946@gregkh/T https://nvd.nist.gov/vuln/detail/CVE-2022-50773 https://www.cve.org/CVERecord?id=CVE-2022-50773
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 `Low`

Wed, 24 Dec 2025 13:15:00 +0000

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: ALSA: mts64: fix possible null-ptr-defer in snd_mts64_interrupt I got a null-ptr-defer error report when I do the following tests on the qemu platform: make defconfig and CONFIG_PARPORT=m, CONFIG_PARPORT_PC=m, CONFIG_SND_MTS64=m Then making test scripts: cat>test_mod1.sh<<EOF modprobe snd-mts64 modprobe snd-mts64 EOF Executing the script, perhaps several times, we will get a null-ptr-defer report, as follow: syzkaller:~# ./test_mod.sh snd_mts64: probe of snd_mts64.0 failed with error -5 modprobe: ERROR: could not insert 'snd_mts64': No such device BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] PREEMPT SMP PTI CPU: 0 PID: 205 Comm: modprobe Not tainted 6.1.0-rc8-00588-g76dcd734eca2 #6 Call Trace: <IRQ> snd_mts64_interrupt+0x24/0xa0 [snd_mts64] parport_irq_handler+0x37/0x50 [parport] __handle_irq_event_percpu+0x39/0x190 handle_irq_event_percpu+0xa/0x30 handle_irq_event+0x2f/0x50 handle_edge_irq+0x99/0x1b0 __common_interrupt+0x5d/0x100 common_interrupt+0xa0/0xc0 </IRQ> <TASK> asm_common_interrupt+0x22/0x40 RIP: 0010:_raw_write_unlock_irqrestore+0x11/0x30 parport_claim+0xbd/0x230 [parport] snd_mts64_probe+0x14a/0x465 [snd_mts64] platform_probe+0x3f/0xa0 really_probe+0x129/0x2c0 __driver_probe_device+0x6d/0xc0 driver_probe_device+0x1a/0xa0 __device_attach_driver+0x7a/0xb0 bus_for_each_drv+0x62/0xb0 __device_attach+0xe4/0x180 bus_probe_device+0x82/0xa0 device_add+0x550/0x920 platform_device_add+0x106/0x220 snd_mts64_attach+0x2e/0x80 [snd_mts64] port_check+0x14/0x20 [parport] bus_for_each_dev+0x6e/0xc0 __parport_register_driver+0x7c/0xb0 [parport] snd_mts64_module_init+0x31/0x1000 [snd_mts64] do_one_initcall+0x3c/0x1f0 do_init_module+0x46/0x1c6 load_module+0x1d8d/0x1e10 __do_sys_finit_module+0xa2/0xf0 do_syscall_64+0x37/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd </TASK> Kernel panic - not syncing: Fatal exception in interrupt Rebooting in 1 seconds.. The mts wa not initialized during interrupt, we add check for mts to fix this bug.
Title		ALSA: mts64: fix possible null-ptr-defer in snd_mts64_interrupt
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/0649129359219ce6ff380ec401f87308485c6ae3 https://git.kernel.org/stable/c/06ec592389f2be3199779ab823c4323dcfd2121f https://git.kernel.org/stable/c/1a763c748acd5540ccc43306c57c9c6c5fb60884 https://git.kernel.org/stable/c/250eed7b9994d79f9c409f954dbd08e88f5afd83 https://git.kernel.org/stable/c/7e91667db38abb056da5a496d40fbd044c66bed2 https://git.kernel.org/stable/c/b471fe61da523a15e4cb60fa81f5a2377e4bad98 https://git.kernel.org/stable/c/c7e9624d90bf20f1eed6b228949396d614b94020 https://git.kernel.org/stable/c/cba633b24a98d957e8190ef8bc4d4cdb4f6e9313 https://git.kernel.org/stable/c/cf2ea3c86ad90d63d1c572b43e1ca9276b0357ad

Projects

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MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2025-12-24T13:06:03.533Z

Updated: 2025-12-24T13:06:03.533Z

Reserved: 2025-12-24T13:02:21.547Z

Link: CVE-2022-50773

Vulnrichment

No data.

NVD

Status : Received

Published: 2025-12-24T13:16:04.120

Modified: 2025-12-24T13:16:04.120

Link: CVE-2022-50773

Redhat

Severity : Low

Publid Date: 2025-12-24T00:00:00Z

Links: CVE-2022-50773 - Bugzilla

OpenCVE Enrichment

No data.

Weaknesses

No weakness.

Metrics

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

Affected Vendors & Products

Projects

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