CVE-2026-53288

CVE-2026-53288 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-674.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: arm64: Reserve an extra page for early kernel mapping The final part of [data, end) segment may overflow into the next page of init_pg_end[1] which is the gap page before early_init_stack[2]: [1] crash_arm64_v9.0.1> vtop ffffffed00601000 VIRTUAL PHYSICAL ffffffed00601000 83401000 PAGE DIRECTORY: ffffffecffd62000 PGD: ffffffecffd62da0 => 10000000833fb003 PMD: ffffff80033fb018 => 10000000833fe003 PTE: ffffff80033fe008 => 68000083401f03 PAGE: 83401000 PTE PHYSICAL FLAGS 68000083401f03 83401000 (VALID|SHARED|AF|NG|PXN|UXN) PAGE PHYSICAL MAPPING INDEX CNT FLAGS fffffffec00d0040 83401000 0 0 1 4000 reserved [2] ffffffed002c8000 (r) __pi__data ffffffed0054e000 (d) __pi___bss_start ffffffed005f5000 (b) __pi_init_pg_dir ffffffed005fe000 (b) __pi_init_pg_end ffffffed005ff000 (B) early_init_stack ffffffed00608000 (b) __pi__end For 4K pages, the early kernel mapping may use 2MB block entries but the kernel segments are only 64KB aligned. Segment boundaries that fall within a 2MB block therefore require a PTE table so that different attributes can be applied on either side of the boundary. KERNEL_SEGMENT_COUNT still correctly counts the five permanent kernel VMAs registered by declare_kernel_vmas(). However, since commit 5973a62efa34 ("arm64: map [_text, _stext) virtual address range non-executable+read-only"), the early mapper also maps [_text, _stext) separately from [_stext, _etext). This adds one more early-only split and can require one more page-table page than the existing EARLY_SEGMENT_EXTRA_PAGES allowance reserves. Increase the 4K-page early mapping allowance by one page to cover that additional split. [[email protected]: rewrote part of the commit log] [[email protected]: expanded the code comment]

Frequently asked questions

What is CVE-2026-53288?
In the Linux kernel, the following vulnerability has been resolved: arm64: Reserve an extra page for early kernel mapping The final part of [data, end) segment may overflow into the next page of init_pg_end[1] which is the gap page before early_init_stack[2]: [1] crash_arm64_v9.0.1> vtop ffffffed00601000 VIRTUAL PHYSICAL ffffffed00601000 83401000 PAGE DIRECTORY: ffffffecffd62000 PGD: ffffffecffd62da0 => 10000000833fb003 PMD: ffffff80033fb018 => 10000000833fe003 PTE: ffffff80033fe008 => 68000083401f03 PAGE: 83401000 PTE PHYSICAL FLAGS 68000083401f03 83401000 (VALID|SHARED|AF|NG|PXN|UXN) PAGE PHYSICAL MAPPING INDEX CNT FLAGS fffffffec00d0040 83401000 0 0 1 4000 reserved [2] ffffffed002c8000 (r) __pi__data ffffffed0054e000 (d) __pi___bss_start ffffffed005f5000 (b) __pi_init_pg_dir ffffffed005fe000 (b) __pi_init_pg_end ffffffed005ff000 (B) early_init_stack ffffffed00608000 (b) __pi__end For 4K pages, the early kernel mapping may use 2MB block entries but the kernel segments are only 64KB aligned. Segment boundaries that fall within a 2MB block therefore require a PTE table so that different attributes can be applied on either side of the boundary. KERNEL_SEGMENT_COUNT still correctly counts the five permanent kernel VMAs registered by declare_kernel_vmas(). However, since commit 5973a62efa34 ("arm64: map [_text, _stext) virtual address range non-executable+read-only"), the early mapper also maps [_text, _stext) separately from [_stext, _etext). This adds one more early-only split and can require one more page-table page than the existing EARLY_SEGMENT_EXTRA_PAGES allowance reserves. Increase the 4K-page early mapping allowance by one page to cover that additional split. [[email protected]: rewrote part of the commit log] [[email protected]: expanded the code comment]
How severe is CVE-2026-53288?
CVE-2026-53288 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-2026-53288 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-53288?
CVE-2026-53288 primarily affects Linux Linux Kernel. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-53288?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-53288 published?
CVE-2026-53288 was published on 2026-06-26 and last updated on 2026-07-08.

References

Affected products (2)

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