CVE-2026-53288
Status: AnalyzedMedium (5.5)—
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
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.
Read full descriptionShow less
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.
[catalin.marinas@arm.com: rewrote part of the commit log] [catalin.marinas@arm.com: expanded the code comment]
Technical details traces, logs and code from the original report
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__endCVSS
- Version: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Base score: 5.5
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days: 0.16%
- Percentile among all scored CVEs: 5
- Score date: 10/3/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
Affected technologies (1)
CWEs
- CWE-674
References
Raw JSON (NVD)
Show
{
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"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: Reserve an extra page for early kernel mapping\n\nThe final part of [data, end) segment may overflow into the next page of\ninit_pg_end[1] which is the gap page before early_init_stack[2]:\n\n[1]\ncrash_arm64_v9.0.1> vtop ffffffed00601000\nVIRTUAL PHYSICAL\nffffffed00601000 83401000\n\nPAGE DIRECTORY: ffffffecffd62000\n PGD: ffffffecffd62da0 => 10000000833fb003\n PMD: ffffff80033fb018 => 10000000833fe003\n PTE: ffffff80033fe008 => 68000083401f03\n PAGE: 83401000\n\n PTE PHYSICAL FLAGS\n68000083401f03 83401000 (VALID|SHARED|AF|NG|PXN|UXN)\n\n PAGE PHYSICAL MAPPING INDEX CNT FLAGS\nfffffffec00d0040 83401000 0 0 1 4000 reserved\n\n[2]\nffffffed002c8000 (r) __pi__data\nffffffed0054e000 (d) __pi___bss_start\nffffffed005f5000 (b) __pi_init_pg_dir\nffffffed005fe000 (b) __pi_init_pg_end\nffffffed005ff000 (B) early_init_stack\nffffffed00608000 (b) __pi__end\n\nFor 4K pages, the early kernel mapping may use 2MB block entries but the\nkernel segments are only 64KB aligned. Segment boundaries that fall\nwithin a 2MB block therefore require a PTE table so that different\nattributes can be applied on either side of the boundary.\n\nKERNEL_SEGMENT_COUNT still correctly counts the five permanent kernel\nVMAs registered by declare_kernel_vmas(). However, since commit\n5973a62efa34 (\"arm64: map [_text, _stext) virtual address range\nnon-executable+read-only\"), the early mapper also maps [_text, _stext)\nseparately from [_stext, _etext). This adds one more early-only split\nand can require one more page-table page than the existing\nEARLY_SEGMENT_EXTRA_PAGES allowance reserves.\n\nIncrease the 4K-page early mapping allowance by one page to cover that\nadditional split.\n\n[catalin.marinas@arm.com: rewrote part of the commit log]\n[catalin.marinas@arm.com: expanded the code comment]"
}
],
"lastModified": "2026-07-08T03:54:34.127",
"configurations": [
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