{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-31466", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-31466", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-04-22T13:53:56.259Z", "updatedAt": "2026-10-15T01:16:28.626Z", "importedAt": "2026-10-24T01:58:02.025Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "mm/huge_memory: fix folio isn't locked in softleaf_to_folio()", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/huge_memory: fix folio isn't locked in softleaf_to_folio()\n\nOn arm64 server, we found folio that get from migration entry isn't locked\nin softleaf_to_folio(). This issue triggers when mTHP splitting and\nzap_nonpresent_ptes() races, and the root cause is lack of memory barrier\nin softleaf_to_folio(). The race is as follows:\n\n\tCPU0 CPU1\n\ndeferred_split_scan() zap_nonpresent_ptes()\n lock folio\n split_folio()\n unmap_folio()\n change ptes to migration entries\n __split_folio_to_order() softleaf_to_folio()\n set flags(including PG_locked) for tail pages folio = pfn_folio(softleaf_to_pfn(entry))\n smp_wmb() VM_WARN_ON_ONCE(!folio_test_locked(folio))\n prep_compound_page() for tail pages\n\nIn __split_folio_to_order(), smp_wmb() guarantees page flags of tail pages\nare visible before the tail page becomes non-compound. smp_wmb() should\nbe paired with smp_rmb() in softleaf_to_folio(), which is missed. As a\nresult, if zap_nonpresent_ptes() accesses migration entry that stores tail\npfn, softleaf_to_folio() may see the updated compound_head of tail page\nbefore page->flags.\n\nThis issue will trigger VM_WARN_ON_ONCE() in pfn_swap_entry_folio()\nbecause of the race between folio split and zap_nonpresent_ptes()\nleading to a folio incorrectly undergoing modification without a folio\nlock being held.\n\nThis is a BUG_ON() before commit 93976a20345b (\"mm: eliminate further\nswapops predicates\"), which in merged in v6.19-rc1.\n\nTo fix it, add missing smp_rmb() if the softleaf entry is migration entry\nin softleaf_to_folio() and softleaf_to_page().\n\n[tujinjiang@huawei.com: update function name and comments]", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b", "status": "affected", "versionType": "git", "lessThan": "426ee10711586617da869c8bb798214965337617" }, { "version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b", "status": "affected", "versionType": "git", "lessThan": "f1acf5887c2bbaf998dc3fe32c72b7a8b84a3ddd" }, { "version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b", "status": "affected", "versionType": "git", "lessThan": "722cfaf6b31d31123439e67b5deac6b1261a3dea" }, { "version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b", "status": "affected", "versionType": "git", "lessThan": "7ddcf4a245c1c5a91fdd9698757e3d95179ffe41" }, { "version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b", "status": "affected", "versionType": "git", "lessThan": "b8c49ad888892ad7b77062b9c102b799a3e9b4f8" }, { "version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b", "status": "affected", "versionType": "git", "lessThan": "7ad1997b9bc8032603df8f091761114479285769" }, { "version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b", "status": "affected", "versionType": "git", "lessThan": "8bfb8414e9f2ce6f5f2f0e3d0da52f2d132128e7" }, { "version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b", "status": "affected", "versionType": "git", "lessThan": "4c5e7f0fcd592801c9cc18f29f80fbee84eb8669" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "4.5", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "4.5" }, { "version": "5.10.253", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.203", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.168", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.134", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.81", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.21", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "6.19.11", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.19.*" }, { "version": "7.0", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }