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CVE PROGRAM SOURCE RECORD7.8 High

CVE-2026-63875

arm64: tlb: Flush walk cache when unsharing PMD tables

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In 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 |

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 6495204f8219a57859669d618b25d06176d5a872 to < dced308d7d6a0de1c09d2058f38f1aaaf5cbb914affected
  • ce4cf24761467756462c0e1dbe4a5e9c9eb520fc to < 47490bbb05c8c0e09cc3cfd237d8934ffc340583affected
  • daa6707b71a2da23a82979fa21f788aeb706f1a2 to < 0199c9d57861f17b556b6cba1f765c7cce79745baffected
  • ff37dd18ce7739a26aab0cc2d31006a45e6bde63 to < d766a49d9b55705c4737cd8bb5d3faa2d31330fdaffected
  • da06bb0ca45b1ca6f1ab55023e34e61a520337f3 to < 8ca7284da0e67b3e71d90ec17f08286774245ad9affected
  • 9b671f6f432be07c0ddd66e437d6d0e0db684f83 to < fe93e907b1af03cc229a80aa64a570a103d2b279affected
  • 8ce720d5bd91e9dc16db3604aa4b1bf76770a9a1 to < 48125cd9c55cbe297b59fd1f9bda48b0960bd181affected
  • 8ce720d5bd91e9dc16db3604aa4b1bf76770a9a1 to < c2ff4764e03e7a8d758352f4aceb8fe1be6ac971affected
  • 5.10.253 to < 5.10.259affected
  • 5.15.203 to < 5.15.210affected
  • 6.1.167 to < 6.1.176affected
  • 6.6.127 to < 6.6.143affected
  • 6.12.74 to < 6.12.93affected
  • 6.18.13 to < 6.18.35affected

Linux Linux

Default version status: affected

  • 6.19affected
  • 0 to < 6.19unaffected
  • 5.10.259 to ≤ 5.10.*unaffected
  • 5.15.210 to ≤ 5.15.*unaffected
  • 6.1.176 to ≤ 6.1.*unaffected
  • 6.6.143 to ≤ 6.6.*unaffected
  • 6.12.93 to ≤ 6.12.*unaffected
  • 6.18.35 to ≤ 6.18.*unaffected
  • 7.0.12 to ≤ 7.0.*unaffected
  • 7.1 to ≤ *unaffected

References