{"id":"CVE-2026-63875","revision":"6b438e26462f43a991cf9a93bb59579b","records":[{"revision":"6b438e26462f43a991cf9a93bb59579b","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-63875","aliases":[],"title":"arm64: tlb: Flush walk cache when unsharing PMD tables","description":"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->unshared_tables=true\nbut the aarch64 tlb_flush() only checked tlb->freed_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                        |","state":0,"publishedAt":"2026-07-19T14:54:48.842+00:00","modifiedAt":"2026-10-19T20:17:53.723+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"arch/arm64/include/asm/tlb.h\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6495204f8219a57859669d618b25d06176d5a872\",\n                            \"lessThan\": \"dced308d7d6a0de1c09d2058f38f1aaaf5cbb914\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"ce4cf24761467756462c0e1dbe4a5e9c9eb520fc\",\n                            \"lessThan\": \"47490bbb05c8c0e09cc3cfd237d8934ffc340583\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"daa6707b71a2da23a82979fa21f788aeb706f1a2\",\n                            \"lessThan\": \"0199c9d57861f17b556b6cba1f765c7cce79745b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"ff37dd18ce7739a26aab0cc2d31006a45e6bde63\",\n                            \"lessThan\": \"d766a49d9b55705c4737cd8bb5d3faa2d31330fd\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"da06bb0ca45b1ca6f1ab55023e34e61a520337f3\",\n                            \"lessThan\": \"8ca7284da0e67b3e71d90ec17f08286774245ad9\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9b671f6f432be07c0ddd66e437d6d0e0db684f83\",\n                            \"lessThan\": \"fe93e907b1af03cc229a80aa64a570a103d2b279\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"8ce720d5bd91e9dc16db3604aa4b1bf76770a9a1\",\n                            \"lessThan\": \"48125cd9c55cbe297b59fd1f9bda48b0960bd181\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"8ce720d5bd91e9dc16db3604aa4b1bf76770a9a1\",\n                            \"lessThan\": \"c2ff4764e03e7a8d758352f4aceb8fe1be6ac971\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"5.10.253\",\n                            \"lessThan\": \"5.10.259\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.203\",\n                            \"lessThan\": \"5.15.210\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.167\",\n                            \"lessThan\": \"6.1.176\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.127\",\n                            \"lessThan\": \"6.6.143\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.74\",\n                            \"lessThan\": \"6.12.93\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.13\",\n                            \"lessThan\": \"6.18.35\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"arch/arm64/include/asm/tlb.h\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.19\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.19\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.259\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.210\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.176\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.143\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.93\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.35\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.0.12\",\n                            \"lessThanOrEqual\": \"7.0.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"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"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-63875","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-63875","identifiers":["CVE-2026-63875"]},"retained":false,"historicalAffected":[]}],"coverage":[]}