CVE-2026-31702

{"id": "CVE-2026-31702", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 1.8}]}, "affected": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "affectedData": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "4c8ff7095bef64fc47e996a938f7d57f9e077da3", "lessThan": "57bc678f36ac03281e877c6b84877b43f964143f", "versionType": "git"}, {"status": "affected", "version": "4c8ff7095bef64fc47e996a938f7d57f9e077da3", "lessThan": "ef57cd3329b40c739b9a2e1a8a21ecc4171c6280", "versionType": "git"}, {"status": "affected", "version": "4c8ff7095bef64fc47e996a938f7d57f9e077da3", "lessThan": "f5154cf3ce1c8193f0c1891d3769f62740cfe6fe", "versionType": "git"}, {"status": "affected", "version": "4c8ff7095bef64fc47e996a938f7d57f9e077da3", "lessThan": "c76cf339b87975ae5b2c06d2d774d5667d25a12a", "versionType": "git"}, {"status": "affected", "version": "4c8ff7095bef64fc47e996a938f7d57f9e077da3", "lessThan": "2c97dcb6147c8f7f25c629b93be1e69617de5d4a", "versionType": "git"}, {"status": "affected", "version": "4c8ff7095bef64fc47e996a938f7d57f9e077da3", "lessThan": "39d4ee19c1e7d753dd655aebee632271b171f43a", "versionType": "git"}], "programFiles": ["fs/f2fs/compress.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "5.6"}, {"status": "unaffected", "version": "0", "lessThan": "5.6", "versionType": "semver"}, {"status": "unaffected", "version": "6.1.175", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.136", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.84", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.18.25", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "7.0.2", "versionType": "semver", "lessThanOrEqual": "7.0.*"}, {"status": "unaffected", "version": "7.1", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["fs/f2fs/compress.c"], "defaultStatus": "affected"}]}], "published": "2026-05-01T14:16:20.140", "references": [{"url": "https://git.kernel.org/stable/c/2c97dcb6147c8f7f25c629b93be1e69617de5d4a", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/39d4ee19c1e7d753dd655aebee632271b171f43a", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/57bc678f36ac03281e877c6b84877b43f964143f", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/c76cf339b87975ae5b2c06d2d774d5667d25a12a", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/ef57cd3329b40c739b9a2e1a8a21ecc4171c6280", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/f5154cf3ce1c8193f0c1891d3769f62740cfe6fe", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-416"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix use-after-free of sbi in f2fs_compress_write_end_io()\n\nIn f2fs_compress_write_end_io(), dec_page_count(sbi, type) can bring\nthe F2FS_WB_CP_DATA counter to zero, unblocking\nf2fs_wait_on_all_pages() in f2fs_put_super() on a concurrent unmount\nCPU. The unmount path then proceeds to call\nf2fs_destroy_page_array_cache(sbi), which destroys\nsbi->page_array_slab via kmem_cache_destroy(), and eventually\nkfree(sbi). Meanwhile, the bio completion callback is still executing:\nwhen it reaches page_array_free(sbi, ...), it dereferences\nsbi->page_array_slab \u2014 a destroyed slab cache \u2014 to call\nkmem_cache_free(), causing a use-after-free.\n\nThis is the same class of bug as CVE-2026-23234 (which fixed the\nequivalent race in f2fs_write_end_io() in data.c), but in the\ncompressed writeback completion path that was not covered by that fix.\n\nFix this by moving dec_page_count() to after page_array_free(), so\nthat all sbi accesses complete before the counter decrement that can\nunblock unmount. For non-last folios (where atomic_dec_return on\ncic->pending_pages is nonzero), dec_page_count is called immediately\nbefore returning \u2014 page_array_free is not reached on this path, so\nthere is no post-decrement sbi access. For the last folio,\npage_array_free runs while the F2FS_WB_CP_DATA counter is still\nnonzero (this folio has not yet decremented it), keeping sbi alive,\nand dec_page_count runs as the final operation."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nf2fs: corrige el uso despu\u00e9s de liberaci\u00f3n de sbi en f2fs_compress_write_end_io()\n\nEn f2fs_compress_write_end_io(), dec_page_count(sbi, type) puede llevar el contador F2FS_WB_CP_DATA a cero, desbloqueando f2fs_wait_on_all_pages() en f2fs_put_super() en una CPU de desmontaje concurrente. La ruta de desmontaje luego procede a llamar a f2fs_destroy_page_array_cache(sbi), que destruye sbi -> page_array_slab a trav\u00e9s de kmem_cache_destroy(), y finalmente kfree(sbi). Mientras tanto, la devoluci\u00f3n de llamada de finalizaci\u00f3n de bio todav\u00eda se est\u00e1 ejecutando: cuando llega a page_array_free(sbi, ...), desreferencia sbi -> page_array_slab - una cach\u00e9 de slab destruida - para llamar a kmem_cache_free(), causando un uso despu\u00e9s de liberaci\u00f3n.\n\nEsta es la misma clase de error que CVE-2026-23234 (que corrigi\u00f3 la condici\u00f3n de carrera equivalente en f2fs_write_end_io() en data.c), pero en la ruta de finalizaci\u00f3n de escritura diferida comprimida que no fue cubierta por esa correcci\u00f3n.\n\nCorrige esto moviendo dec_page_count() a despu\u00e9s de page_array_free(), para que todos los accesos a sbi se completen antes del decremento del contador que puede desbloquear el desmontaje. Para folios no finales (donde atomic_dec_return en cic -> pending_pages es distinto de cero), dec_page_count se llama inmediatamente antes de regresar - page_array_free no se alcanza en esta ruta, por lo que no hay acceso a sbi posterior al decremento. Para el \u00faltimo folio, page_array_free se ejecuta mientras el contador F2FS_WB_CP_DATA todav\u00eda es distinto de cero (este folio a\u00fan no lo ha decrementado), manteniendo sbi vivo, y dec_page_count se ejecuta como la operaci\u00f3n final."}], "lastModified": "2026-11-11T21:10:00.200", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "C8FF327A-4809-4F9C-B926-FF8D39DAAA1D", "versionEndExcluding": "6.6.136", "versionStartIncluding": "5.6"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "D4ECA0DE-AFF5-4688-B219-4CA2336CA5B7", "versionEndExcluding": "6.12.84", "versionStartIncluding": "6.7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "8B0A7E0E-F6D8-45DB-8CD9-01839FE40A6C", "versionEndExcluding": "6.18.25", "versionStartIncluding": "6.13"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "1BD58F1E-7C20-4C0D-92A2-FAC5CBFBE8A8", "versionEndExcluding": "7.0.2", "versionStartIncluding": "6.19"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "B1EF7059-E670-45F4-B422-54C40FA86390"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "0D38F0BF-A728-4133-A358-D44A2F7EE6D6"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}