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CVE Record

CVE-2025-71143: clk: samsung: exynos-clkout: Assign .num before accessing .hws

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.

UnknownCVSS not scoredNot KEV-listedUpdated
Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel correctness bug in the Samsung Exynos clock-output driver. A metadata field is initialized too late, causing bounds-sanitizer warnings when the driver touches its clock array. Sources describe warning cleanup, not known compromise, data exposure, or remote attack. Business impact is mainly kernel maintenance and device stability assurance.

Executive priority

Treat as routine kernel hygiene unless your fleet includes Samsung Exynos-based devices. No source indicates active exploitation or broad enterprise exposure, but affected embedded or mobile-adjacent systems should receive normal kernel update handling.

Technical view

The exynos_clkout_probe() path accesses clk_hw_onecell_data.hws before initializing .num. After __counted_by annotation, UBSAN_BOUNDS treats .num as the element count, so early access triggers an array-index-out-of-bounds warning. The fix moves .num initialization before the first .hws access.

Likely exposure

Exposure is likely limited to Linux systems using the Samsung Exynos clkout driver on affected kernel versions listed by the CVE source. General servers and non-Exynos devices are unlikely to exercise this path.

Exploitation context

The provided sources do not report active exploitation, KEV listing, public exploit activity, privilege impact, or remote attackability. Evidence supports a sanitizer-detected initialization-order bug rather than a demonstrated attack path.

Researcher notes

Key evidence is the kernel commit text: .num must be initialized before .hws access because __counted_by informs UBSAN_BOUNDS. The CVE record lacks CVSS, CWE, exploit details, and operational impact analysis, so severity confidence is constrained.

Mitigation direction

  • Apply the relevant Linux stable kernel fix or downstream vendor kernel update.
  • Prioritize Samsung Exynos platforms or kernels enabling the exynos-clkout driver.
  • Check distribution and device-vendor advisories for packaged fix availability.
  • Avoid inventing local patches; use the referenced upstream stable commits.

Validation and detection

  • Inventory Linux kernel versions against the CVE affected-version data.
  • Confirm whether the Samsung exynos-clkout driver is built or loaded.
  • Review boot and test logs for UBSAN_BOUNDS warnings in clk-exynos-clkout.c.
  • Verify the deployed kernel includes one of the referenced stable fixes.
Prepared
Confidence
medium
Sources
6

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
5Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxf316cdff8d677db9ad9c90acb44c4cd535b0ee27, f316cdff8d677db9ad9c90acb44c4cd535b0ee27, f316cdff8d677db9ad9c90acb44c4cd535b0ee27, f316cdff8d677db9ad9c90acb44c4cd535b0ee27unaffected
LinuxLinux6.6, 0, 6.6.120, 6.12.64, 6.18.4, 6.19affected
Weakness

CWE details

No CWE listed

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