{"affected":[{"defaultStatus":"unaffected","product":"Linux","source":"CNA: Linux","vendor":"Linux","versions":[{"lessThan":"426ee10711586617da869c8bb798214965337617","status":"affected","version":"e9b61f19858a5d6c42ce2298cf138279375d0d9b","versionType":"git"},{"lessThan":"f1acf5887c2bbaf998dc3fe32c72b7a8b84a3ddd","status":"affected","version":"e9b61f19858a5d6c42ce2298cf138279375d0d9b","versionType":"git"},{"lessThan":"722cfaf6b31d31123439e67b5deac6b1261a3dea","status":"affected","version":"e9b61f19858a5d6c42ce2298cf138279375d0d9b","versionType":"git"},{"lessThan":"7ddcf4a245c1c5a91fdd9698757e3d95179ffe41","status":"affected","version":"e9b61f19858a5d6c42ce2298cf138279375d0d9b","versionType":"git"},{"lessThan":"b8c49ad888892ad7b77062b9c102b799a3e9b4f8","status":"affected","version":"e9b61f19858a5d6c42ce2298cf138279375d0d9b","versionType":"git"},{"lessThan":"7ad1997b9bc8032603df8f091761114479285769","status":"affected","version":"e9b61f19858a5d6c42ce2298cf138279375d0d9b","versionType":"git"},{"lessThan":"8bfb8414e9f2ce6f5f2f0e3d0da52f2d132128e7","status":"affected","version":"e9b61f19858a5d6c42ce2298cf138279375d0d9b","versionType":"git"},{"lessThan":"4c5e7f0fcd592801c9cc18f29f80fbee84eb8669","status":"affected","version":"e9b61f19858a5d6c42ce2298cf138279375d0d9b","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","source":"CNA: Linux","vendor":"Linux","versions":[{"status":"affected","version":"4.5"},{"lessThan":"4.5","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.253","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.203","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.168","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.134","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.81","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.21","versionType":"semver"},{"lessThanOrEqual":"6.19.*","status":"unaffected","version":"6.19.11","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.0","versionType":"original_commit_for_fix"}]},{"defaultStatus":"unknown","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","source":"ADP: siemens-SADP","vendor":"Siemens","versions":[{"lessThan":"*","status":"affected","version":"V3.1.6","versionType":"custom"}]},{"defaultStatus":"unknown","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","source":"ADP: siemens-SADP","vendor":"Siemens","versions":[{"lessThan":"*","status":"affected","version":"V3.1.5","versionType":"custom"}]},{"defaultStatus":"unknown","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","source":"ADP: siemens-SADP","vendor":"Siemens","versions":[{"lessThan":"*","status":"affected","version":"V3.1.7","versionType":"custom"}]},{"defaultStatus":"unknown","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","source":"ADP: siemens-SADP","vendor":"Siemens","versions":[{"lessThan":"*","status":"affected","version":"V3.1.6","versionType":"custom"}]},{"defaultStatus":"unknown","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","source":"ADP: siemens-SADP","vendor":"Siemens","versions":[{"lessThan":"*","status":"affected","version":"V3.1.5","versionType":"custom"}]},{"defaultStatus":"unknown","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","source":"ADP: siemens-SADP","vendor":"Siemens","versions":[{"lessThan":"*","status":"affected","version":"V3.1.7","versionType":"custom"}]},{"defaultStatus":"unknown","product":"SIPLUS S7-1500 CPU 1518-4 PN/DP MFP","source":"ADP: siemens-SADP","vendor":"Siemens","versions":[{"lessThan":"*","status":"affected","version":"V3.1.6","versionType":"custom"}]},{"defaultStatus":"unknown","product":"SIPLUS S7-1500 CPU 1518-4 PN/DP MFP","source":"ADP: siemens-SADP","vendor":"Siemens","versions":[{"lessThan":"*","status":"affected","version":"V3.1.5","versionType":"custom"}]},{"defaultStatus":"unknown","product":"SIPLUS S7-1500 CPU 1518-4 PN/DP MFP","source":"ADP: siemens-SADP","vendor":"Siemens","versions":[{"lessThan":"*","status":"affected","version":"V3.1.7","versionType":"custom"}]}],"cveId":"CVE-2026-31466","cwes":[],"description":"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]","epss":{"date":"2026-11-05","percentile":0.00573,"score":0.00094},"exploits":[],"kev":null,"metrics":[],"modifiedAt":1793915100806,"publishedAt":1776866036259,"references":[{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/426ee10711586617da869c8bb798214965337617"},{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/f1acf5887c2bbaf998dc3fe32c72b7a8b84a3ddd"},{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/722cfaf6b31d31123439e67b5deac6b1261a3dea"},{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/7ddcf4a245c1c5a91fdd9698757e3d95179ffe41"},{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/b8c49ad888892ad7b77062b9c102b799a3e9b4f8"},{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/7ad1997b9bc8032603df8f091761114479285769"},{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/8bfb8414e9f2ce6f5f2f0e3d0da52f2d132128e7"},{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/4c5e7f0fcd592801c9cc18f29f80fbee84eb8669"},{"source":"ADP: siemens-SADP","tags":[],"url":"https://cert-portal.siemens.com/productcert/html/ssa-082556.html"},{"source":"ADP: siemens-SADP","tags":[],"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html"},{"source":"ADP: siemens-SADP","tags":[],"url":"https://cert-portal.siemens.com/productcert/html/ssa-457936.html"}],"remediation":[],"revision":"36b01e3aebd74ba9f35514d2db1ba7993b4c1898acc3370408b30e91398bde5c","sources":[{"modifiedAt":1793915100806,"name":"CNA: Linux","retrievedAt":1793917055833,"url":"https://www.cve.org/CVERecord?id=CVE-2026-31466"},{"modifiedAt":null,"name":"FIRST EPSS","retrievedAt":1793917074535,"url":"https://api.first.org/data/v1/epss?cve=CVE-2026-31466"}],"ssvc":{"assessedAt":1793914470187,"automatable":"no","exploitation":"none","source":"ADP: CISA-ADP","technicalImpact":"partial"},"status":"published","title":"mm/huge_memory: fix folio isn't locked in softleaf_to_folio()","updatedAt":1793917074535}