Strix
26.1K

CVE-2022-50091

MEDIUMCVSS 5.5/10EPSS 0.20%

Last modified

CVE-2022-50091 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: locking/csd_lock: Change csdlock_debug from early_param to __setup The csdlock_debug kernel-boot parameter is parsed by the early_param() function csdlock_debug(). If set, csdlock_debug() invokes static_branch_enable() to enable csd_lock_wait feature, which triggers a panic on arm64 for kernels built with CONFIG_SPARSEMEM=y and CONFIG_SPARSEMEM_VMEMMAP=n. With CONFIG_SPARSEMEM_VMEMMAP=n, __nr_to_section is called in static_key_enable() and returns NULL, resulting in a NULL dereference because mem_section is initialized only later in sparse_init(). This is also a problem for powerpc because early_param() functions are invoked earlier than jump_label_init(), also resulting in static_key_enable() failures. EPSS estimates a 0.20% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: locking/csd_lock: Change csdlock_debug from early_param to __setup The csdlock_debug kernel-boot parameter is parsed by the early_param() function csdlock_debug(). If set, csdlock_debug() invokes static_branch_enable() to enable csd_lock_wait feature, which triggers a panic on arm64 for kernels built with CONFIG_SPARSEMEM=y and CONFIG_SPARSEMEM_VMEMMAP=n. With CONFIG_SPARSEMEM_VMEMMAP=n, __nr_to_section is called in static_key_enable() and returns NULL, resulting in a NULL dereference because mem_section is initialized only later in sparse_init(). This is also a problem for powerpc because early_param() functions are invoked earlier than jump_label_init(), also resulting in static_key_enable() failures. These failures cause the warning "static key 'xxx' used before call to jump_label_init()". Thus, early_param is too early for csd_lock_wait to run static_branch_enable(), so changes it to __setup to fix these.

Metrics

CVSS 3.1
5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability
0.20%

10.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
LinuxLinux Kernel>= 5.13, < 5.15.61
LinuxLinux Kernel>= 5.16, < 5.18.18
LinuxLinux Kernel>= 5.19, < 5.19.2

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2022-50091?
In the Linux kernel, the following vulnerability has been resolved: locking/csd_lock: Change csdlock_debug from early_param to __setup The csdlock_debug kernel-boot parameter is parsed by the early_param() function csdlock_debug(). If set, csdlock_debug() invokes static_branch_enable() to enable csd_lock_wait feature, which triggers a panic on arm64 for kernels built with CONFIG_SPARSEMEM=y and CONFIG_SPARSEMEM_VMEMMAP=n. With CONFIG_SPARSEMEM_VMEMMAP=n, __nr_to_section is called in static_key_enable() and returns NULL, resulting in a NULL dereference because mem_section is initialized only later in sparse_init(). This is also a problem for powerpc because early_param() functions are invoked earlier than jump_label_init(), also resulting in static_key_enable() failures. These failures cause the warning "static key 'xxx' used before call to jump_label_init()". Thus, early_param is too early for csd_lock_wait to run static_branch_enable(), so changes it to __setup to fix these.
How severe is CVE-2022-50091?
CVE-2022-50091 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.20% probability of exploitation in the next 30 days.
How do I fix CVE-2022-50091?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2022-50091?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST