FKIE_CVE-2026-63819
Vulnerability from fkie_nvd - Published: 2026-07-19 12:16 - Updated: 2026-07-20 15:16
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to do sanity check on f2fs_get_node_folio_ra()
kernel BUG at fs/f2fs/file.c:845!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5336 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:f2fs_do_truncate_blocks+0x1115/0x1140 fs/f2fs/file.c:845
Code: fc fc 90 0f 0b e8 8b 9d 9a fd 90 0f 0b e8 83 9d 9a fd 48 89 df 48 c7 c6 60 d1 1a 8c e8 54 f1 fc fc 90 0f 0b e8 6c 9d 9a fd 90 <0f> 0b e8 64 9d 9a fd 90 0f 0b 90 e9 93 fd ff ff e8 56 9d 9a fd 90
RSP: 0018:ffffc9000e4474c0 EFLAGS: 00010283
RAX: ffffffff842b1d34 RBX: 0000000000000003 RCX: 0000000000100000
RDX: ffffc9000f03a000 RSI: 0000000000035503 RDI: 0000000000035504
RBP: ffffc9000e447608 R08: ffff8880123b0000 R09: 0000000000000002
R10: 00000000fffffffe R11: 0000000000000002 R12: 0000000000000001
R13: 0000000000000000 R14: 1ffff92001c88ea0 R15: 00000000ffff039c
FS: 00007f7e02ee36c0(0000) GS:ffff88808c887000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff0305c4000 CR3: 0000000012d4c000 CR4: 0000000000352ef0
Call Trace:
<TASK>
f2fs_truncate_blocks+0x10a/0x300 fs/f2fs/file.c:882
f2fs_truncate+0x471/0x7c0 fs/f2fs/file.c:940
f2fs_evict_inode+0xa3f/0x1ac0 fs/f2fs/inode.c:907
evict+0x61e/0xb10 fs/inode.c:841
f2fs_fill_super+0x5f43/0x78f0 fs/f2fs/super.c:5224
get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694
vfs_get_tree+0x92/0x2a0 fs/super.c:1754
fc_mount fs/namespace.c:1193 [inline]
do_new_mount_fc fs/namespace.c:3758 [inline]
do_new_mount+0x341/0xd30 fs/namespace.c:3834
do_mount fs/namespace.c:4167 [inline]
__do_sys_mount fs/namespace.c:4383 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4360
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
count = ADDRS_PER_PAGE(dn.node_folio, inode);
count -= dn.ofs_in_node;
f2fs_bug_on(sbi, count < 0);
The fuzz test will trigger above bug_on in f2fs.
The root cause should be: in the corrupted inode, there is a direct node
which has the same ino and nid in its footer, so in f2fs_do_truncate_blocks(),
after f2fs_get_dnode_of_data() finds such dnode:
1) ADDRS_PER_PAGE(dn.node_folio, inode) will return 923
2) once dn.ofs_in_node points to addr[923, 1017]
Then it will trigger the system panic.
Let's introduce NODE_TYPE_NON_IXNODE to indicate current node should
not be an inode or xattr node, and then use it in below path to detect
inconsistent node chain in inode mapping table:
- f2fs_do_truncate_blocks
- f2fs_get_dnode_of_data
- f2fs_get_node_folio_ra
- __get_node_folio
- f2fs_sanity_check_node_footer
- case NODE_TYPE_NON_IXNODE -> check whether it is inode|xnode
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/f2fs/f2fs.h",
"fs/f2fs/node.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "406c28af75123432d38cf9bbaa6f1476f7b14770",
"status": "affected",
"version": "e05df3b115e7308afbca652769b54e4549fcc723",
"versionType": "git"
},
{
"lessThan": "0cc21c1ffe15b4156b0bf744f32fd1faef0b7c73",
"status": "affected",
"version": "e05df3b115e7308afbca652769b54e4549fcc723",
"versionType": "git"
},
{
"lessThan": "8712353ed80f87271d732297567dcdbe4b84e8c7",
"status": "affected",
"version": "e05df3b115e7308afbca652769b54e4549fcc723",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/f2fs/f2fs.h",
"fs/f2fs/node.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "3.8"
},
{
"lessThan": "3.8",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.39",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.3",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2-rc1",
"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\nf2fs: fix to do sanity check on f2fs_get_node_folio_ra()\n\nkernel BUG at fs/f2fs/file.c:845!\nOops: invalid opcode: 0000 [#1] SMP KASAN NOPTI\nCPU: 0 UID: 0 PID: 5336 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full)\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\nRIP: 0010:f2fs_do_truncate_blocks+0x1115/0x1140 fs/f2fs/file.c:845\nCode: fc fc 90 0f 0b e8 8b 9d 9a fd 90 0f 0b e8 83 9d 9a fd 48 89 df 48 c7 c6 60 d1 1a 8c e8 54 f1 fc fc 90 0f 0b e8 6c 9d 9a fd 90 \u003c0f\u003e 0b e8 64 9d 9a fd 90 0f 0b 90 e9 93 fd ff ff e8 56 9d 9a fd 90\nRSP: 0018:ffffc9000e4474c0 EFLAGS: 00010283\nRAX: ffffffff842b1d34 RBX: 0000000000000003 RCX: 0000000000100000\nRDX: ffffc9000f03a000 RSI: 0000000000035503 RDI: 0000000000035504\nRBP: ffffc9000e447608 R08: ffff8880123b0000 R09: 0000000000000002\nR10: 00000000fffffffe R11: 0000000000000002 R12: 0000000000000001\nR13: 0000000000000000 R14: 1ffff92001c88ea0 R15: 00000000ffff039c\nFS: 00007f7e02ee36c0(0000) GS:ffff88808c887000(0000) knlGS:0000000000000000\nCS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00007ff0305c4000 CR3: 0000000012d4c000 CR4: 0000000000352ef0\nCall Trace:\n \u003cTASK\u003e\n f2fs_truncate_blocks+0x10a/0x300 fs/f2fs/file.c:882\n f2fs_truncate+0x471/0x7c0 fs/f2fs/file.c:940\n f2fs_evict_inode+0xa3f/0x1ac0 fs/f2fs/inode.c:907\n evict+0x61e/0xb10 fs/inode.c:841\n f2fs_fill_super+0x5f43/0x78f0 fs/f2fs/super.c:5224\n get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694\n vfs_get_tree+0x92/0x2a0 fs/super.c:1754\n fc_mount fs/namespace.c:1193 [inline]\n do_new_mount_fc fs/namespace.c:3758 [inline]\n do_new_mount+0x341/0xd30 fs/namespace.c:3834\n do_mount fs/namespace.c:4167 [inline]\n __do_sys_mount fs/namespace.c:4383 [inline]\n __se_sys_mount+0x31d/0x420 fs/namespace.c:4360\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\n\tcount = ADDRS_PER_PAGE(dn.node_folio, inode);\n\n\tcount -= dn.ofs_in_node;\n\tf2fs_bug_on(sbi, count \u003c 0);\n\nThe fuzz test will trigger above bug_on in f2fs.\n\nThe root cause should be: in the corrupted inode, there is a direct node\nwhich has the same ino and nid in its footer, so in f2fs_do_truncate_blocks(),\nafter f2fs_get_dnode_of_data() finds such dnode:\n1) ADDRS_PER_PAGE(dn.node_folio, inode) will return 923\n2) once dn.ofs_in_node points to addr[923, 1017]\nThen it will trigger the system panic.\n\nLet\u0027s introduce NODE_TYPE_NON_IXNODE to indicate current node should\nnot be an inode or xattr node, and then use it in below path to detect\ninconsistent node chain in inode mapping table:\n\n- f2fs_do_truncate_blocks\n - f2fs_get_dnode_of_data\n - f2fs_get_node_folio_ra\n - __get_node_folio\n - f2fs_sanity_check_node_footer\n - case NODE_TYPE_NON_IXNODE -\u003e check whether it is inode|xnode"
}
],
"id": "CVE-2026-63819",
"lastModified": "2026-07-20T15:16:48.823",
"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": "2026-07-19T12:16:54.980",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/0cc21c1ffe15b4156b0bf744f32fd1faef0b7c73"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/406c28af75123432d38cf9bbaa6f1476f7b14770"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/8712353ed80f87271d732297567dcdbe4b84e8c7"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
Loading…