CVE-2026-63875

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 |

• linux linux kernel (>= 5.10.253 < 5.10.259) • linux linux kernel (>= 5.15.203 < 5.15.210) • linux linux kernel (>= 6.1.167 < 6.1.176) • linux linux kernel (>= 6.6.127 < 6.6.143) • linux linux kernel (>= 6.12.74 < 6.12.93) • linux linux kernel (>= 6.18.13 < 6.18.35) • linux linux kernel (>= 6.19.1 < 7.0.12) • linux linux kernel 6.19 • linux linux kernel 7.1