CVE-2026-80656

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-80656", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-26T14:34:25.780Z", "datePublished": "2026-08-28T06:49:02.596Z", "dateUpdated": "2026-08-29T06:21:45.266Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-29T06:21:45.266Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhfsplus: Add a sanity check for btree node size\n\nSyzbot reported an uninit-value bug in [1] with a corrupted HFS+ image,\nduring the file system mounting process, specifically while loading the\ncatalog, a corrupted node_size value of 1 caused the rec_off argument\npassed to hfs_bnode_read_u16() (within hfs_bnode_find()) to be excessively\nlarge. Consequently, the function failed to return a valid value to\ninitialize the off variable, triggering the bug [1].\n\nEvery node starts from BTree node descriptor: struct hfs_bnode_desc.\nSo, the size of node cannot be lesser than that. However, technical\nspecification declares that: \"The node size (which is expressed in bytes)\nmust be power of two, from 512 through 32,768, inclusive.\" Add a check\nfor btree node size base on technical specification.\n\n[1]\nBUG: KMSAN: uninit-value in hfsplus_bnode_find+0x141c/0x1600 fs/hfsplus/bnode.c:584\n hfsplus_bnode_find+0x141c/0x1600 fs/hfsplus/bnode.c:584\n hfsplus_btree_open+0x169a/0x1e40 fs/hfsplus/btree.c:382\n hfsplus_fill_super+0x111f/0x2770 fs/hfsplus/super.c:553\n get_tree_bdev_flags+0x6e6/0x920 fs/super.c:1694\n get_tree_bdev+0x38/0x50 fs/super.c:1717\n hfsplus_get_tree+0x35/0x40 fs/hfsplus/super.c:709\n vfs_get_tree+0xb3/0x5d0 fs/super.c:1754\n fc_mount fs/namespace.c:1193 [inline]"}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - The vulnerable hfs_btree_open\u2192hfs_bnode_find path is reached only via local mount(2)/vfs_get_tree on a block/loop/USB device (hfsplus_fill_super); there is no network-facing consumer of hfsplus btree parsing.\nAC:L - A crafted on-disk btree header node_size of 1 is a valid power-of-two and deterministically makes rec_off negative (wrapped to a huge u32), so hfs_bnode_read_u16 skips filling its stack buffer and KMSAN reports uninit-value at mount without races or external preconditions.\nPR:L - hfsplus is FS_REQUIRES_DEV without FS_USERNS_MOUNT; the highest-impact scenario is an unprivileged local user supplying an HFS+ USB/SD image that udisks2 or a desktop automounter mounts, or a loop image attached through session polkit helpers\u2014no real root in init_ns is needed by the attacker.\nUI:N - The attacker inserts removable media or supplies the image that gets mounted; mount-time catalog/extent btree loading fires automatically during fill_super with no separate victim action beyond routine automount behavior.\nS:U - Uninitialized-value consumption and any mount-time parser fault stay within the host kernel parsing the attacker's filesystem; no VM escape, IOMMU bypass, or sandbox boundary is crossed.\nC:H - Before the fix, invalid node_size lets hfs_bnode_read return without initializing the hfs_bnode_read_u16 buffer; the resulting garbage off value drives subsequent btree record-offset parsing and bounded node reads that consume uninitialized stack bytes\u2014a memory-safety defect class treated as arbitrary read potential per kernel CVSS guidance.\nI:H - Attacker-controlled sub-512 power-of-two node_size corrupts btree rec_off arithmetic; uninitialized or crafted record offsets can pass hfs_bnode_find checks and seed inconsistent in-memory btree nodes whose corrupted offsets propagate into further mount-time bmap and page-cache accesses.\nA:H - Syzbot/KMSAN builds panic on the uninit-value at hfsplus_bnode_find; even on production kernels a crafted image causes mount failure after kernel error logging, and repeated automount of malicious removable media can deny access to the volume and waste mount resources."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/hfsplus/btree.c", "include/linux/hfs_common.h"], "versions": [{"version": "8ad2c6a36ac4328072377906a47ea0bff11e4032", "lessThan": "306265eb9384d2c224f1b14d83a29323f0eab6d1", "status": "affected", "versionType": "git"}, {"version": "8ad2c6a36ac4328072377906a47ea0bff11e4032", "lessThan": "3f95e2661574ff13f099dd13456751933c280628", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/hfsplus/btree.c", "include/linux/hfs_common.h"], "versions": [{"version": "7.1", "status": "affected"}, {"version": "0", "lessThan": "7.1", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.1", "versionEndExcluding": "7.1.5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.1", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/306265eb9384d2c224f1b14d83a29323f0eab6d1"}, {"url": "https://git.kernel.org/stable/c/3f95e2661574ff13f099dd13456751933c280628"}], "title": "hfsplus: Add a sanity check for btree node size", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/hfsplus/btree.c", "include/linux/hfs_common.h"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "306265eb9384d2c224f1b14d83a29323f0eab6d1", "status": "affected", "version": "8ad2c6a36ac4328072377906a47ea0bff11e4032", "versionType": "git"}, {"lessThan": "3f95e2661574ff13f099dd13456751933c280628", "status": "affected", "version": "8ad2c6a36ac4328072377906a47ea0bff11e4032", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/hfsplus/btree.c", "include/linux/hfs_common.h"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "7.1"}, {"lessThan": "7.1", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.5", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhfsplus: Add a sanity check for btree node size\n\nSyzbot reported an uninit-value bug in [1] with a corrupted HFS+ image,\nduring the file system mounting process, specifically while loading the\ncatalog, a corrupted node_size value of 1 caused the rec_off argument\npassed to hfs_bnode_read_u16() (within hfs_bnode_find()) to be excessively\nlarge. Consequently, the function failed to return a valid value to\ninitialize the off variable, triggering the bug [1].\n\nEvery node starts from BTree node descriptor: struct hfs_bnode_desc.\nSo, the size of node cannot be lesser than that. However, technical\nspecification declares that: \"The node size (which is expressed in bytes)\nmust be power of two, from 512 through 32,768, inclusive.\" Add a check\nfor btree node size base on technical specification.\n\n[1]\nBUG: KMSAN: uninit-value in hfsplus_bnode_find+0x141c/0x1600 fs/hfsplus/bnode.c:584\n hfsplus_bnode_find+0x141c/0x1600 fs/hfsplus/bnode.c:584\n hfsplus_btree_open+0x169a/0x1e40 fs/hfsplus/btree.c:382\n hfsplus_fill_super+0x111f/0x2770 fs/hfsplus/super.c:553\n get_tree_bdev_flags+0x6e6/0x920 fs/super.c:1694\n get_tree_bdev+0x38/0x50 fs/super.c:1717\n hfsplus_get_tree+0x35/0x40 fs/hfsplus/super.c:709\n vfs_get_tree+0xb3/0x5d0 fs/super.c:1754\n fc_mount fs/namespace.c:1193 [inline]"}], "id": "CVE-2026-80656", "lastModified": "2026-08-29T07:16:48.437", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-08-28T08:16:50.700", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/306265eb9384d2c224f1b14d83a29323f0eab6d1"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/3f95e2661574ff13f099dd13456751933c280628"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: hfsplus: Add a sanity check for btree node size", "id": "2525431", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2525431"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-824", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nhfsplus: Add a sanity check for btree node size\nSyzbot reported an uninit-value bug in [1] with a corrupted HFS+ image,\nduring the file system mounting process, specifically while loading the\ncatalog, a corrupted node_size value of 1 caused the rec_off argument\npassed to hfs_bnode_read_u16() (within hfs_bnode_find()) to be excessively\nlarge. Consequently, the function failed to return a valid value to\ninitialize the off variable, triggering the bug [1].\nEvery node starts from BTree node descriptor: struct hfs_bnode_desc.\nSo, the size of node cannot be lesser than that. However, technical\nspecification declares that: \"The node size (which is expressed in bytes)\nmust be power of two, from 512 through 32,768, inclusive.\" Add a check\nfor btree node size base on technical specification.\n[1]\nBUG: KMSAN: uninit-value in hfsplus_bnode_find+0x141c/0x1600 fs/hfsplus/bnode.c:584\nhfsplus_bnode_find+0x141c/0x1600 fs/hfsplus/bnode.c:584\nhfsplus_btree_open+0x169a/0x1e40 fs/hfsplus/btree.c:382\nhfsplus_fill_super+0x111f/0x2770 fs/hfsplus/super.c:553\nget_tree_bdev_flags+0x6e6/0x920 fs/super.c:1694\nget_tree_bdev+0x38/0x50 fs/super.c:1717\nhfsplus_get_tree+0x35/0x40 fs/hfsplus/super.c:709\nvfs_get_tree+0xb3/0x5d0 fs/super.c:1754\nfc_mount fs/namespace.c:1193 [inline]", "A flaw was found in the Linux kernel's hfsplus filesystem. A local attacker could provide a specially crafted and corrupted HFS+ image. When attempting to mount this image, a malformed btree node size value could lead to the use of an uninitialized value within the kernel. This could result in a kernel crash, causing a denial of service (DoS) to the system."], "name": "CVE-2026-80656", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-28T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-80656\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-80656\nhttps://lore.kernel.org/linux-cve-announce/2026082844-CVE-2026-80656-09e1@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[8ad2c6a36ac4328072377906a47ea0bff11e4032,306265eb9384d2c224f1b14d83a29323f0eab6d1)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[8ad2c6a36ac4328072377906a47ea0bff11e4032,3f95e2661574ff13f099dd13456751933c280628)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "7.1"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,7.1)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.5,8.0.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-08-28T11:15:03.528529+00:00", "updated": "2026-09-02T05:30:08.144213+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}