CVE-2022-48953

CVE-2022-48953 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: rtc: cmos: Fix event handler registration ordering issue Because acpi_install_fixed_event_handler() enables the event automatically on success, it is incorrect to call it before the handler routine passed to it is ready to handle events. Unfortunately, the rtc-cmos driver does exactly the incorrect thing by calling cmos_wake_setup(), which passes rtc_handler() to acpi_install_fixed_event_handler(), before cmos_do_probe(), because rtc_handler() uses dev_get_drvdata() to get to the cmos object pointer and the driver data pointer is only populated in cmos_do_probe(). This leads to a NULL pointer dereference in rtc_handler() on boot if the RTC fixed event happens to be active at the init time. To address this issue, change the initialization ordering of the driver so that cmos_wake_setup() is always called after a successful cmos_do_probe() call. While at it, change cmos_pnp_probe() to call cmos_do_probe() after the initial if () statement used for computing the IRQ argument to be passed to cmos_do_probe() which is cleaner than calling it in each branch of that if () (local variable "irq" can be of type int, because it is passed to that function as an argument of type int). Note that commit 6492fed7d8c9 ("rtc: rtc-cmos: Do not check ACPI_FADT_LOW_POWER_S0") caused this issue to affect a larger number of systems, because previously it only affected systems with ACPI_FADT_LOW_POWER_S0 set, but it is present regardless of that commit.

Frequently asked questions

What is CVE-2022-48953?
In the Linux kernel, the following vulnerability has been resolved: rtc: cmos: Fix event handler registration ordering issue Because acpi_install_fixed_event_handler() enables the event automatically on success, it is incorrect to call it before the handler routine passed to it is ready to handle events. Unfortunately, the rtc-cmos driver does exactly the incorrect thing by calling cmos_wake_setup(), which passes rtc_handler() to acpi_install_fixed_event_handler(), before cmos_do_probe(), because rtc_handler() uses dev_get_drvdata() to get to the cmos object pointer and the driver data pointer is only populated in cmos_do_probe(). This leads to a NULL pointer dereference in rtc_handler() on boot if the RTC fixed event happens to be active at the init time. To address this issue, change the initialization ordering of the driver so that cmos_wake_setup() is always called after a successful cmos_do_probe() call. While at it, change cmos_pnp_probe() to call cmos_do_probe() after the initial if () statement used for computing the IRQ argument to be passed to cmos_do_probe() which is cleaner than calling it in each branch of that if () (local variable "irq" can be of type int, because it is passed to that function as an argument of type int). Note that commit 6492fed7d8c9 ("rtc: rtc-cmos: Do not check ACPI_FADT_LOW_POWER_S0") caused this issue to affect a larger number of systems, because previously it only affected systems with ACPI_FADT_LOW_POWER_S0 set, but it is present regardless of that commit.
How severe is CVE-2022-48953?
CVE-2022-48953 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2022-48953 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-48953?
CVE-2022-48953 primarily affects Linux Linux Kernel. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2022-48953?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2022-48953 have an EU (EUVD) identifier?
Yes. CVE-2022-48953 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2022-53832.
When was CVE-2022-48953 published?
CVE-2022-48953 was published on 2024-10-21 and last updated on 2026-06-17.

References

Affected products (9)

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