CVE-2025-71143 clk: samsung: exynos-clkout: Assign .num before accessing .hws
A missing initialization in the Samsung Exynos clock driver triggers a UBSAN bounds warning, potentially causing a kernel panic or denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-71143?
CVE-2025-71143 is a high-severity vulnerability in Linux kernel, published on 14 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
clk: samsung: exynos-clkout: Assign .num before accessing .hws
Commit f316cdff8d67 ("clk: Annotate struct clk_hw_onecell_data with __counted_by") annotated the hws member of 'struct clk_hw_onecell_data' with __counted_by, which informs the bounds sanitizer (UBSAN_BOUNDS) about the number of elements in .hws[], so that it can warn when .hws[] is accessed out of bounds. As noted in that change, the __counted_by member must be initialized with the number of elements before the first array access happens, otherwise there will be a warning from each access prior to the initialization because the number of elements is zero. This occurs in exynos_clkout_probe() due to .num being assigned after .hws[] has been accessed:
UBSAN: array-index-out-of-bounds in drivers/clk/samsung/clk-exynos-clkout.c:178:18 index 0 is out of range for type 'clk_hw *[*]'
Move the .num initialization to before the first access of .hws[], clearing up the warning.
Weakness: CWE-129
Which versions are affected by CVE-2025-71143?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-71143?
Apply the vendor's patch.
Is CVE-2025-71143 being exploited?
There is no known exploitation of CVE-2025-71143 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-71143, DEBIAN-CVE-2025-71143, GHSA-7w9g-xvfr-q799, ROOT-OS-DEBIAN-13-CVE-2025-71143, ROOT-OS-UBUNTU-2404-CVE-2025-71143, UBUNTU-CVE-2025-71143.