{ "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-2026-63796", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-63796", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-07-19T12:02:04.634Z", "updatedAt": "2026-10-19T20:07:47.316Z", "importedAt": "2026-10-24T01:58:20.586Z", "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": "ocfs2: reject oversized group bitmap descriptors", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: reject oversized group bitmap descriptors\n\nocfs2_validate_gd_parent() only bounds bg_bits against the parent\nallocator's chain geometry. A malicious descriptor can still claim a\nbg_size/bg_bits pair that exceeds the bitmap bytes that physically fit in\nthe group descriptor block, so later bitmap scans and bit updates can run\npast bg_bitmap.\n\nAdd a physical-cap check based on ocfs2_group_bitmap_size() for the parent\nallocator type and reject descriptors whose bg_size or bg_bits exceed that\ncapacity. Keep the existing chain geometry check so both the on-disk\nbitmap layout and the allocator metadata must agree before the descriptor\nis used.\n\nValidation reproduced this kernel report:\nKASAN use-after-free in _find_next_bit+0x7f/0xc0\nRead of size 8\nCall trace:\n dump_stack_lvl+0x66/0xa0 (?:?)\n print_report+0xd0/0x630 (?:?)\n _find_next_bit+0x7f/0xc0 (?:?)\n srso_alias_return_thunk+0x5/0xfbef5 (?:?)\n __virt_addr_valid+0x188/0x2f0 (?:?)\n kasan_report+0xe4/0x120 (?:?)\n ocfs2_find_max_contig_free_bits+0x35/0x70 (fs/ocfs2/suballoc.c:1375)\n ocfs2_block_group_set_bits+0x472/0x4b0 (fs/ocfs2/suballoc.c:1457)\n ocfs2_cluster_group_search+0x16b/0x440 (fs/ocfs2/suballoc.c:86)\n ocfs2_bg_discontig_fix_result+0x1ef/0x230 (fs/ocfs2/suballoc.c:1786)\n ocfs2_search_chain+0x8f8/0x10a0 (fs/ocfs2/suballoc.c:1886)\n get_page_from_freelist+0x70e/0x2370 (?:?)\n lock_release+0xc6/0x290 (?:?)\n do_raw_spin_unlock+0x9a/0x100 (?:?)\n kasan_unpoison+0x27/0x60 (?:?)\n __bfs+0x147/0x240 (?:?)\n get_page_from_freelist+0x83d/0x2370 (?:?)\n ocfs2_claim_suballoc_bits+0x38c/0xe70 (fs/ocfs2/suballoc.c:96)\n sched_domains_numa_masks_clear+0x70/0xd0 (?:?)\n check_irq_usage+0xe8/0xb70 (?:?)\n __ocfs2_claim_clusters+0x18d/0x4c0 (fs/ocfs2/suballoc.c:2497)\n check_path+0x24/0x50 (?:?)\n rcu_is_watching+0x20/0x50 (?:?)\n check_prev_add+0xfd/0xd00 (?:?)\n ocfs2_add_clusters_in_btree+0x17d/0x810 (fs/ocfs2/suballoc.c:?)\n __folio_batch_add_and_move+0x1f5/0x3d0 (?:?)\n ocfs2_add_inode_data+0xd9/0x120 (fs/ocfs2/suballoc.c:?)\n filemap_add_folio+0x105/0x1f0 (?:?)\n ocfs2_write_begin_nolock+0x29f7/0x2f80 (fs/ocfs2/suballoc.c:3043)\n ocfs2_read_inode_block+0xb5/0x110 (fs/ocfs2/suballoc.c:?)\n down_write+0xf5/0x180 (?:?)\n ocfs2_write_begin+0x180/0x240 (fs/ocfs2/suballoc.c:?)\n __mark_inode_dirty+0x758/0x9a0 (?:?)\n inode_to_bdi+0x41/0x90 (?:?)\n balance_dirty_pages_ratelimited_flags+0xf8/0x1d0 (?:?)\n generic_perform_write+0x252/0x440 (?:?)\n mnt_put_write_access_file+0x16/0x70 (?:?)\n file_update_time_flags+0xe4/0x200 (?:?)\n ocfs2_file_write_iter+0x80a/0x1320 (fs/ocfs2/suballoc.c:?)\n lock_acquire+0x184/0x2f0 (?:?)\n ksys_write+0xd2/0x170 (?:?)\n apparmor_file_permission+0xf5/0x310 (?:?)\n read_zero+0x8d/0x140 (?:?)\n lock_is_held_type+0x8f/0x100 (?:?)", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c", "status": "affected", "versionType": "git", "lessThan": "336340a0f8a141df8a4eb21a5a86f8ffb87769f6" }, { "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c", "status": "affected", "versionType": "git", "lessThan": "296c6a42b1174395935ca4cfe8f393e37b698d54" }, { "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c", "status": "affected", "versionType": "git", "lessThan": "d2cd59fa848f9f13796ef214d3b1b5ca9a3fe21e" }, { "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c", "status": "affected", "versionType": "git", "lessThan": "c5a125eadba05ba421c4b55e68da22b4a40d32b4" }, { "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c", "status": "affected", "versionType": "git", "lessThan": "8f9903b0cdbb3155a8899410330b4b4d583a7a5c" }, { "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c", "status": "affected", "versionType": "git", "lessThan": "4cd57ebee395041099fcdfcabb00749ce38d8b27" }, { "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c", "status": "affected", "versionType": "git", "lessThan": "99c21e7263248c3f084756bfae08163cc5d6c62f" }, { "version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c", "status": "affected", "versionType": "git", "lessThan": "9bd541e09dffff27e5bec0f9f45b0228173a5375" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "2.6.16", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "2.6.16" }, { "version": "5.10.260", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.211", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.177", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.144", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.95", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.38", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.1.3", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.1.*" }, { "version": "7.2", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }