arm64: tlb: Flush walk cache when unsharing PMD tables

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-63875
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-19 16:17:04 UTC
Updated2026-07-20 15:16:53 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: arm64: tlb: Flush walk cache when unsharing PMD tables When huge_pmd_unshare() is called to unshare a PMD table, the tlb_unshare_pmd_ptdesc() function sets tlb->unshared_tables=true but the aarch64 tlb_flush() only checked tlb->freed_tables to determine whether to use TLBF_NONE (vae1is, invalidates walk cache) or TLBF_NOWALKCACHE (vale1is, leaf-only). This caused the stale PMD page table entry to remain in the walk cache after unshare, potentially leading to incorrect page table walks. Fix by including unshared_tables in the check, so that when unsharing tables, TLBF_NONE is used and the walk cache is properly invalidated. Here is the detailed distinction between vae1is and vale1is: | Instruction Combination | Actual Invalidation Scope | | ------------------------ | --------------------------------------------------| | `VAE1IS` + TTL=`0` | All entries at all levels (full invalidation) | | `VAE1IS` + TTL=`2` (L2) | Non-leaf at Level 0/1 + leaf at Level 2 | | `VALE1IS` + TTL=`0` | Leaf entries at all levels (non-leaf not cleared) | | `VALE1IS` + TTL=`2` (L2) | Leaf entry at Level 2 only |

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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

EPSS: 0.002100000 probability, percentile 0.113680000 (date 2026-07-20)

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

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 6495204f8219a57859669d618b25d06176d5a872 dced308d7d6a0de1c09d2058f38f1aaaf5cbb914 git Not specified
CNA Linux Linux affected ce4cf24761467756462c0e1dbe4a5e9c9eb520fc 47490bbb05c8c0e09cc3cfd237d8934ffc340583 git Not specified
CNA Linux Linux affected daa6707b71a2da23a82979fa21f788aeb706f1a2 0199c9d57861f17b556b6cba1f765c7cce79745b git Not specified
CNA Linux Linux affected ff37dd18ce7739a26aab0cc2d31006a45e6bde63 d766a49d9b55705c4737cd8bb5d3faa2d31330fd git Not specified
CNA Linux Linux affected da06bb0ca45b1ca6f1ab55023e34e61a520337f3 8ca7284da0e67b3e71d90ec17f08286774245ad9 git Not specified
CNA Linux Linux affected 9b671f6f432be07c0ddd66e437d6d0e0db684f83 fe93e907b1af03cc229a80aa64a570a103d2b279 git Not specified
CNA Linux Linux affected 8ce720d5bd91e9dc16db3604aa4b1bf76770a9a1 48125cd9c55cbe297b59fd1f9bda48b0960bd181 git Not specified
CNA Linux Linux affected 8ce720d5bd91e9dc16db3604aa4b1bf76770a9a1 c2ff4764e03e7a8d758352f4aceb8fe1be6ac971 git Not specified
CNA Linux Linux affected 5.10.253 5.10.259 semver Not specified
CNA Linux Linux affected 5.15.203 5.15.210 semver Not specified
CNA Linux Linux affected 6.1.167 6.1.176 semver Not specified
CNA Linux Linux affected 6.6.127 6.6.143 semver Not specified
CNA Linux Linux affected 6.12.74 6.12.93 semver Not specified
CNA Linux Linux affected 6.18.13 6.18.35 semver Not specified
CNA Linux Linux affected 6.19 Not specified
CNA Linux Linux unaffected 6.19 semver Not specified
CNA Linux Linux unaffected 5.10.259 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.210 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.176 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.143 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.93 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.35 6.18.* semver Not specified
CNA Linux Linux unaffected 7.0.12 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/dced308d7d6a0de1c09d2058f38f1aaaf5cbb914 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/d766a49d9b55705c4737cd8bb5d3faa2d31330fd 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/8ca7284da0e67b3e71d90ec17f08286774245ad9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/fe93e907b1af03cc229a80aa64a570a103d2b279 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/47490bbb05c8c0e09cc3cfd237d8934ffc340583 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c2ff4764e03e7a8d758352f4aceb8fe1be6ac971 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0199c9d57861f17b556b6cba1f765c7cce79745b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/48125cd9c55cbe297b59fd1f9bda48b0960bd181 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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