ocfs2: reject oversized group bitmap descriptors
In the Linux kernel, the following vulnerability has been resolved: ocfs2: reject oversized group bitmap descriptors ocfs2_validate_gd_parent() only bounds bg_bits against the parent allocator's chain geometry. A malicious descriptor can still claim a bg_size/bg_bits pair that exceeds the bitmap bytes that physically fit in the group descriptor block, so later bitmap scans and bit updates can run past bg_bitmap. Add a physical-cap check based on ocfs2_group_bitmap_size() for the parent allocator type and reject descriptors whose bg_size or bg_bits exceed that capacity. Keep the existing chain geometry check so both the on-disk bitmap layout and the allocator metadata must agree before the descriptor is used. Validation reproduced this kernel report: KASAN use-after-free in _find_next_bit+0x7f/0xc0 Read of size 8 Call trace: dump_stack_lvl+0x66/0xa0 (?:?) print_report+0xd0/0x630 (?:?) _find_next_bit+0x7f/0xc0 (?:?) srso_alias_return_thunk+0x5/0xfbef5 (?:?) __virt_addr_valid+0x188/0x2f0 (?:?) kasan_report+0xe4/0x120 (?:?) ocfs2_find_max_contig_free_bits+0x35/0x70 (fs/ocfs2/suballoc.c:1375) ocfs2_block_group_set_bits+0x472/0x4b0 (fs/ocfs2/suballoc.c:1457) ocfs2_cluster_group_search+0x16b/0x440 (fs/ocfs2/suballoc.c:86) ocfs2_bg_discontig_fix_result+0x1ef/0x230 (fs/ocfs2/suballoc.c:1786) ocfs2_search_chain+0x8f8/0x10a0 (fs/ocfs2/suballoc.c:1886) get_page_from_freelist+0x70e/0x2370 (?:?) lock_release+0xc6/0x290 (?:?) do_raw_spin_unlock+0x9a/0x100 (?:?) kasan_unpoison+0x27/0x60 (?:?
CVE-2026-63796
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-63796
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
"lessThan": "336340a0f8a141df8a4eb21a5a86f8ffb87769f6",
"versionType": "git"
},
{
"status": "affected",
"version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
"lessThan": "296c6a42b1174395935ca4cfe8f393e37b698d54",
"versionType": "git"
},
{
"status": "affected",
"version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
"lessThan": "d2cd59fa848f9f13796ef214d3b1b5ca9a3fe21e",
"versionType": "git"
},
{
"status": "affected",
"version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
"lessThan": "c5a125eadba05ba421c4b55e68da22b4a40d32b4",
"versionType": "git"
},
{
"status": "affected",
"version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
"lessThan": "8f9903b0cdbb3155a8899410330b4b4d583a7a5c",
"versionType": "git"
},
{
"status": "affected",
"version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
"lessThan": "4cd57ebee395041099fcdfcabb00749ce38d8b27",
"versionType": "git"
},
{
"status": "affected",
"version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
"lessThan": "99c21e7263248c3f084756bfae08163cc5d6c62f",
"versionType": "git"
},
{
"status": "affected",
"version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
"lessThan": "9bd541e09dffff27e5bec0f9f45b0228173a5375",
"versionType": "git"
}
],
"programFiles": [
"fs/ocfs2/suballoc.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.16"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "2.6.16",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.260",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.211",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.177",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.144",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.95",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.38",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.3",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/ocfs2/suballoc.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-63796
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #40829 · Revision 1
- Added to Heist Feed
- Publisher date