{"id":"CVE-2026-63875","summary":"arm64: tlb: Flush walk cache when unsharing PMD tables","details":"In the Linux kernel, the following vulnerability has been resolved:\n\narm64: tlb: Flush walk cache when unsharing PMD tables\n\nWhen huge_pmd_unshare() is called to unshare a PMD table, the\ntlb_unshare_pmd_ptdesc() function sets tlb-\u003eunshared_tables=true\nbut the aarch64 tlb_flush() only checked tlb-\u003efreed_tables to\ndetermine whether to use TLBF_NONE (vae1is, invalidates walk\ncache) or TLBF_NOWALKCACHE (vale1is, leaf-only).\n\nThis caused the stale PMD page table entry to remain in the walk cache\nafter unshare, potentially leading to incorrect page table walks.\n\nFix by including unshared_tables in the check, so that when\nunsharing tables, TLBF_NONE is used and the walk cache is properly\ninvalidated.\n\nHere is the detailed distinction between vae1is and vale1is:\n\n| Instruction Combination  | Actual Invalidation Scope                         |\n| ------------------------ | --------------------------------------------------|\n| `VAE1IS`  + TTL=`0`      | All entries at all levels (full invalidation)     |\n| `VAE1IS`  + TTL=`2` (L2) | Non-leaf at Level 0/1 + leaf at Level 2           |\n| `VALE1IS` + TTL=`0`      | Leaf entries at all levels (non-leaf not cleared) |\n| `VALE1IS` + TTL=`2` (L2) | Leaf entry at Level 2 only                        |","modified":"2026-07-22T05:29:49.604804279Z","published":"2026-07-19T14:54:48.842Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63875.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0199c9d57861f17b556b6cba1f765c7cce79745b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/47490bbb05c8c0e09cc3cfd237d8934ffc340583"},{"type":"WEB","url":"https://git.kernel.org/stable/c/48125cd9c55cbe297b59fd1f9bda48b0960bd181"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8ca7284da0e67b3e71d90ec17f08286774245ad9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c2ff4764e03e7a8d758352f4aceb8fe1be6ac971"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d766a49d9b55705c4737cd8bb5d3faa2d31330fd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/dced308d7d6a0de1c09d2058f38f1aaaf5cbb914"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fe93e907b1af03cc229a80aa64a570a103d2b279"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63875.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63875"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6495204f8219a57859669d618b25d06176d5a872"},{"fixed":"dced308d7d6a0de1c09d2058f38f1aaaf5cbb914"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"ce4cf24761467756462c0e1dbe4a5e9c9eb520fc"},{"fixed":"47490bbb05c8c0e09cc3cfd237d8934ffc340583"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"daa6707b71a2da23a82979fa21f788aeb706f1a2"},{"fixed":"0199c9d57861f17b556b6cba1f765c7cce79745b"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"ff37dd18ce7739a26aab0cc2d31006a45e6bde63"},{"fixed":"d766a49d9b55705c4737cd8bb5d3faa2d31330fd"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"da06bb0ca45b1ca6f1ab55023e34e61a520337f3"},{"fixed":"8ca7284da0e67b3e71d90ec17f08286774245ad9"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"9b671f6f432be07c0ddd66e437d6d0e0db684f83"},{"fixed":"fe93e907b1af03cc229a80aa64a570a103d2b279"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"8ce720d5bd91e9dc16db3604aa4b1bf76770a9a1"},{"fixed":"48125cd9c55cbe297b59fd1f9bda48b0960bd181"},{"fixed":"c2ff4764e03e7a8d758352f4aceb8fe1be6ac971"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5.10.253"},{"fixed":"5.10.259"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5.15.203"},{"fixed":"5.15.210"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.1.167"},{"fixed":"6.1.176"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.6.127"},{"fixed":"6.6.143"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.12.74"},{"fixed":"6.12.93"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.18.13"},{"fixed":"6.18.35"}]}],"versions":["v5.10.258","v5.10.257","v5.10.256","v5.10.255","v5.10.254","v5.10.253","v5.15.209","v5.15.208","v5.15.207","v5.15.206","v5.15.205","v5.15.204","v5.15.203","v6.1.175","v6.1.174","v6.1.173","v6.1.172","v6.1.171","v6.1.170","v6.1.169","v6.1.168","v6.1.167","v6.6.142","v6.6.141","v6.6.140","v6.6.139","v6.6.138","v6.6.137","v6.6.136","v6.6.135","v6.6.134","v6.6.133","v6.6.132","v6.6.131","v6.6.130","v6.6.129","v6.6.128","v6.6.127","v6.12.92","v6.12.91","v6.12.90","v6.12.89","v6.12.88","v6.12.87","v6.12.86","v6.12.85","v6.12.84","v6.12.83","v6.12.82","v6.12.81","v6.12.80","v6.12.79","v6.12.78","v6.12.77","v6.12.76","v6.12.75","v6.12.74","v6.18.34","v6.18.33","v6.18.32","v6.18.31","v6.18.30","v6.18.29","v6.18.28","v6.18.27","v6.18.26","v6.18.25","v6.18.24","v6.18.23","v6.18.22","v6.18.21","v6.18.20","v6.18.19","v6.18.18","v6.18.17","v6.18.16","v6.18.15","v6.18.14","v6.18.13"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63875.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.10.259"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.210"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16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