arm64: mm: Handle invalid large leaf mappings correctly
In 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=00e
CVE-2026-31600
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-31600
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "a166563e7ec375b38a0fd3a58f7b77e50a6bc6a8",
"lessThan": "8140b21d19015227a28c255404462f2d3e6edc9a",
"versionType": "git"
},
{
"status": "affected",
"version": "a166563e7ec375b38a0fd3a58f7b77e50a6bc6a8",
"lessThan": "747b6482e4e227fd351197dde6f64a97107a9e52",
"versionType": "git"
},
{
"status": "affected",
"version": "a166563e7ec375b38a0fd3a58f7b77e50a6bc6a8",
"lessThan": "cbea627ea634f41c79d18f0c6d20db66fa93514c",
"versionType": "git"
},
{
"status": "affected",
"version": "a166563e7ec375b38a0fd3a58f7b77e50a6bc6a8",
"lessThan": "15bfba1ad77fad8e45a37aae54b3c813b33fe27c",
"versionType": "git"
}
],
"programFiles": [
"arch/arm64/include/asm/pgtable-prot.h",
"arch/arm64/include/asm/pgtable.h",
"arch/arm64/mm/mmu.c",
"arch/arm64/mm/pageattr.c",
"arch/arm64/mm/trans_pgd.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.18"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.18",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.18.24",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.14",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0.1",
"versionType": "semver",
"lessThanOrEqual": "7.0.*"
},
{
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"arch/arm64/include/asm/pgtable-prot.h",
"arch/arm64/include/asm/pgtable.h",
"arch/arm64/mm/mmu.c",
"arch/arm64/mm/pageattr.c",
"arch/arm64/mm/trans_pgd.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-31600
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #39928 · Revision 1
- Added to Heist Feed
- Publisher date