arm64: mm: Handle invalid large leaf mappings correctly

Summary

CVECVE-2026-31600
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-24 15:16:38 UTC
Updated2026-04-29 20:14:32 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: arm64: mm: Handle invalid large leaf mappings correctly It has been possible for a long time to mark ptes in the linear map as invalid. This is done for secretmem, kfence, realm dma memory un/share, and others, by simply clearing the PTE_VALID bit. But until commit a166563e7ec37 ("arm64: mm: support large block mapping when rodata=full") large leaf mappings were never made invalid in this way. It turns out various parts of the code base are not equipped to handle invalid large leaf mappings (in the way they are currently encoded) and I've observed a kernel panic while booting a realm guest on a BBML2_NOABORT system as a result: [ 15.432706] software IO TLB: Memory encryption is active and system is using DMA bounce buffers [ 15.476896] Unable to handle kernel paging request at virtual address ffff000019600000 [ 15.513762] Mem abort info: [ 15.527245] ESR = 0x0000000096000046 [ 15.548553] EC = 0x25: DABT (current EL), IL = 32 bits [ 15.572146] SET = 0, FnV = 0 [ 15.592141] EA = 0, S1PTW = 0 [ 15.612694] FSC = 0x06: level 2 translation fault [ 15.640644] Data abort info: [ 15.661983] ISV = 0, ISS = 0x00000046, ISS2 = 0x00000000 [ 15.694875] CM = 0, WnR = 1, TnD = 0, TagAccess = 0 [ 15.723740] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 15.755776] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000081f3f000 [ 15.800410] [ffff000019600000] pgd=0000000000000000, p4d=180000009ffff403, pud=180000009fffe403, pmd=00e8000199600704 [ 15.855046] Internal error: Oops: 0000000096000046 [#1] SMP [ 15.886394] Modules linked in: [ 15.900029] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 7.0.0-rc4-dirty #4 PREEMPT [ 15.935258] Hardware name: linux,dummy-virt (DT) [ 15.955612] pstate: 21400005 (nzCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) [ 15.986009] pc : __pi_memcpy_generic+0x128/0x22c [ 16.006163] lr : swiotlb_bounce+0xf4/0x158 [ 16.024145] sp : ffff80008000b8f0 [ 16.038896] x29: ffff80008000b8f0 x28: 0000000000000000 x27: 0000000000000000 [ 16.069953] x26: ffffb3976d261ba8 x25: 0000000000000000 x24: ffff000019600000 [ 16.100876] x23: 0000000000000001 x22: ffff0000043430d0 x21: 0000000000007ff0 [ 16.131946] x20: 0000000084570010 x19: 0000000000000000 x18: ffff00001ffe3fcc [ 16.163073] x17: 0000000000000000 x16: 00000000003fffff x15: 646e612065766974 [ 16.194131] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 [ 16.225059] x11: 0000000000000000 x10: 0000000000000010 x9 : 0000000000000018 [ 16.256113] x8 : 0000000000000018 x7 : 0000000000000000 x6 : 0000000000000000 [ 16.287203] x5 : ffff000019607ff0 x4 : ffff000004578000 x3 : ffff000019600000 [ 16.318145] x2 : 0000000000007ff0 x1 : ffff000004570010 x0 : ffff000019600000 [ 16.349071] Call trace: [ 16.360143] __pi_memcpy_generic+0x128/0x22c (P) [ 16.380310] swiotlb_tbl_map_single+0x154/0x2b4 [ 16.400282] swiotlb_map+0x5c/0x228 [ 16.415984] dma_map_phys+0x244/0x2b8 [ 16.432199] dma_map_page_attrs+0x44/0x58 [ 16.449782] virtqueue_map_page_attrs+0x38/0x44 [ 16.469596] virtqueue_map_single_attrs+0xc0/0x130 [ 16.490509] virtnet_rq_alloc.isra.0+0xa4/0x1fc [ 16.510355] try_fill_recv+0x2a4/0x584 [ 16.526989] virtnet_open+0xd4/0x238 [ 16.542775] __dev_open+0x110/0x24c [ 16.558280] __dev_change_flags+0x194/0x20c [ 16.576879] netif_change_flags+0x24/0x6c [ 16.594489] dev_change_flags+0x48/0x7c [ 16.611462] ip_auto_config+0x258/0x1114 [ 16.628727] do_one_initcall+0x80/0x1c8 [ 16.645590] kernel_init_freeable+0x208/0x2f0 [ 16.664917] kernel_init+0x24/0x1e0 [ 16.680295] ret_from_fork+0x10/0x20 [ 16.696369] Code: 927cec03 cb0e0021 8b0e0042 a9411c26 (a900340c) [ 16.723106] ---[ end trace 0000000000000000 ]--- [ 16.752866] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b [ 16.792556] Kernel Offset: 0x3396ea200000 from 0xffff8000800000 ---truncated---

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.000100000 probability, percentile 0.012230000 (date 2026-04-27)

Problem Types: CWE-476


VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected a166563e7ec375b38a0fd3a58f7b77e50a6bc6a8 8140b21d19015227a28c255404462f2d3e6edc9a git Not specified
CNA Linux Linux affected a166563e7ec375b38a0fd3a58f7b77e50a6bc6a8 747b6482e4e227fd351197dde6f64a97107a9e52 git Not specified
CNA Linux Linux affected a166563e7ec375b38a0fd3a58f7b77e50a6bc6a8 cbea627ea634f41c79d18f0c6d20db66fa93514c git Not specified
CNA Linux Linux affected a166563e7ec375b38a0fd3a58f7b77e50a6bc6a8 15bfba1ad77fad8e45a37aae54b3c813b33fe27c git Not specified
CNA Linux Linux affected 6.18 Not specified
CNA Linux Linux unaffected 6.18 semver Not specified
CNA Linux Linux unaffected 6.18.24 6.18.* semver Not specified
CNA Linux Linux unaffected 6.19.14 6.19.* semver Not specified
CNA Linux Linux unaffected 7.0.1 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/15bfba1ad77fad8e45a37aae54b3c813b33fe27c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/cbea627ea634f41c79d18f0c6d20db66fa93514c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/747b6482e4e227fd351197dde6f64a97107a9e52 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/8140b21d19015227a28c255404462f2d3e6edc9a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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