CVE-2026-63875arm64: tlb: Flush walk cache when unsharing PMD tables
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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 |
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 6495204f8219a57859669d618b25d06176d5a872 before dced308d7d6a0de1c09d2058f38f1aaaf5cbb914; from ce4cf24761467756462c0e1dbe4a5e9c9eb520fc before 47490bbb05c8c0e09cc3cfd237d8934ffc340583; from daa6707b71a2da23a82979fa21f788aeb706f1a2 before 0199c9d57861f17b556b6cba1f765c7cce79745b; from ff37dd18ce7739a26aab0cc2d31006a45e6bde63 before d766a49d9b55705c4737cd8bb5d3faa2d31330fd; from da06bb0ca45b1ca6f1ab55023e34e61a520337f3 before 8ca7284da0e67b3e71d90ec17f08286774245ad9; from 9b671f6f432be07c0ddd66e437d6d0e0db684f83 before fe93e907b1af03cc229a80aa64a570a103d2b279; from 8ce720d5bd91e9dc16db3604aa4b1bf76770a9a1 before 48125cd9c55cbe297b59fd1f9bda48b0960bd181; from 8ce720d5bd91e9dc16db3604aa4b1bf76770a9a1 before c2ff4764e03e7a8d758352f4aceb8fe1be6ac971; and 6 more ranges | CNA record |
References
- https://git.kernel.org/stable/c/dced308d7d6a0de1c09d2058f38f1aaaf5cbb914
- https://git.kernel.org/stable/c/47490bbb05c8c0e09cc3cfd237d8934ffc340583
- https://git.kernel.org/stable/c/0199c9d57861f17b556b6cba1f765c7cce79745b
- https://git.kernel.org/stable/c/d766a49d9b55705c4737cd8bb5d3faa2d31330fd
- https://git.kernel.org/stable/c/8ca7284da0e67b3e71d90ec17f08286774245ad9
- https://git.kernel.org/stable/c/fe93e907b1af03cc229a80aa64a570a103d2b279
- https://git.kernel.org/stable/c/48125cd9c55cbe297b59fd1f9bda48b0960bd181
- https://git.kernel.org/stable/c/c2ff4764e03e7a8d758352f4aceb8fe1be6ac971
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.