{"schema":"threatline.record/2","record":{"id":"CVE-2026-93233","aliases":[],"summary":"drm/nouveau/dmem: fix callocated underflow on large folio split","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/nouveau/dmem: fix callocated underflow on large folio split\n\nnouveau_dmem_folio_free() drops chunk->callocated once per freed folio,\nwhile a large (compound) device-private folio is only counted once when\nit is allocated.  When such a folio is split, the mm core invokes\n->folio_split() (nouveau_dmem_folio_split()) once for each new\nsub-folio, but the hook only fixes up the sub-folio metadata and leaves\nchunk->callocated unchanged.\n\nEach resulting sub-folio is later freed separately, so after a split\nthe single allocation (+1) is met by N frees (-N), leaving\nchunk->callocated short by N-1.  On the first split/free cycle it\nunderflows: WARN_ON(!chunk->callocated) fires, the unsigned counter\nwraps and never returns to zero, so the chunk can no longer be\nreclaimed (nouveau_dmem_fini() also warns on the leaked count).\n\nAccount for the new sub-folio in the split hook, under the same lock as\nnouveau_dmem_folio_free(), so the count stays balanced.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93233","source_modified_at":"2026-10-19T09:07:44.949Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"c3228747107705d47c7e9a03598a434a0380cb73","lessThan":"0163b92946d0a7c816f619c57a4d9867954dd106","status":"affected","versionType":"git"},{"version":"c3228747107705d47c7e9a03598a434a0380cb73","lessThan":"c2256c044a1df39c8aad4dd2d6f709b2533e2d7a","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93233","source_modified_at":"2026-10-19T09:07:44.949Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"6.19","status":"affected"},{"version":"0","lessThan":"6.19","status":"unaffected","versionType":"semver"},{"version":"7.2.5","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93233","source_modified_at":"2026-10-19T09:07:44.949Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"0163b92946d0a7c816f619c57a4d9867954dd106","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00155,"percentile":0.04317,"score_date":"2026-10-23"},"published_at":"2026-09-24T15:32:51.743Z","modified_at":"2026-10-19T09:07:44.949Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-93233","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-19T09:07:44.949Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-93233","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/0163b92946d0a7c816f619c57a4d9867954dd106"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/c2256c044a1df39c8aad4dd2d6f709b2533e2d7a"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T09:07:44.949Z","content_hash":"543f23778e691e16e5d8a249f15b721755ebaeec21e5b154273726b647a2b1f4"}}