CVE-2022-50344
Estado: ModificadaMedia (5.5)—
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix null-ptr-deref in ext4_write_info
To solve this problem, we use ext4_journal_start_sb directly to avoid s_root being used.
Detalles técnicos trazas, registros y código del informe original
I caught a null-ptr-deref bug as follows:
==================================================================
KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f]
CPU: 1 PID: 1589 Comm: umount Not tainted 5.10.0-02219-dirty #339
RIP: 0010:ext4_write_info+0x53/0x1b0
[...]
Call Trace:
dquot_writeback_dquots+0x341/0x9a0
ext4_sync_fs+0x19e/0x800
__sync_filesystem+0x83/0x100
sync_filesystem+0x89/0xf0
generic_shutdown_super+0x79/0x3e0
kill_block_super+0xa1/0x110
deactivate_locked_super+0xac/0x130
deactivate_super+0xb6/0xd0
cleanup_mnt+0x289/0x400
__cleanup_mnt+0x16/0x20
task_work_run+0x11c/0x1c0
exit_to_user_mode_prepare+0x203/0x210
syscall_exit_to_user_mode+0x5b/0x3a0
do_syscall_64+0x59/0x70
entry_SYSCALL_64_after_hwframe+0x44/0xa9
==================================================================
Above issue may happen as follows:
-------------------------------------
exit_to_user_mode_prepare
task_work_run
__cleanup_mnt
cleanup_mnt
deactivate_super
deactivate_locked_super
kill_block_super
generic_shutdown_super
shrink_dcache_for_umount
dentry = sb->s_root
sb->s_root = NULL <--- Here set NULL
sync_filesystem
__sync_filesystem
sb->s_op->sync_fs > ext4_sync_fs
dquot_writeback_dquots
sb->dq_op->write_info > ext4_write_info
ext4_journal_start(d_inode(sb->s_root), EXT4_HT_QUOTA, 2)
d_inode(sb->s_root)
s_root->d_inode <--- Null pointer dereferenceCVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Puntuación base: 5.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.16%
- Percentil entre todas las CVEs puntuadas: 5
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- CWE-476
- CWE-476
Referencias
- https://git.kernel.org/stable/c/3638aa1c7d87c0ca0aef23cf58cae2c48e7daca4
- https://git.kernel.org/stable/c/4a657319cfabd6199fd0b7b65bbebf6ded7a11c1
- https://git.kernel.org/stable/c/533c60a0b97cee5daab376933f486207e6680fb7
- https://git.kernel.org/stable/c/947264e00c46de19a016fd81218118c708fed2f3
- https://git.kernel.org/stable/c/bb420e8afc854d2a1caaa23a0c129839acfb7888
- https://git.kernel.org/stable/c/dc451578446afd03c0c21913993c08898a691435
- https://git.kernel.org/stable/c/f34ab95162763cd7352f46df169296eec28b688d
- https://git.kernel.org/stable/c/f4b5ff0b794aa94afac7269c494550ca2f66511b
- https://git.kernel.org/stable/c/f9c1f248607d5546075d3f731e7607d5571f2b60
JSON original (NVD)
Mostrar
{
"id": "CVE-2022-50344",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2022-50344",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-01-14T18:20:39.263791Z"
}
}
],
"cvssMetricV31": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 5.5,
"attackVector": "LOCAL",
"baseSeverity": "MEDIUM",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "LOW",
"confidentialityImpact": "NONE"
},
"impactScore": 3.6,
"exploitabilityScore": 1.8
},
{
"type": "Secondary",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 5.5,
"attackVector": "LOCAL",
"baseSeverity": "MEDIUM",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "LOW",
"confidentialityImpact": "NONE"
},
"impactScore": 3.6,
"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": "a1177825719ccef3f76ef39bbfd5ebb6087d53c7",
"lessThan": "dc451578446afd03c0c21913993c08898a691435",
"versionType": "git"
},
{
"status": "affected",
"version": "a1177825719ccef3f76ef39bbfd5ebb6087d53c7",
"lessThan": "f4b5ff0b794aa94afac7269c494550ca2f66511b",
"versionType": "git"
},
{
"status": "affected",
"version": "a1177825719ccef3f76ef39bbfd5ebb6087d53c7",
"lessThan": "947264e00c46de19a016fd81218118c708fed2f3",
"versionType": "git"
},
{
"status": "affected",
"version": "a1177825719ccef3f76ef39bbfd5ebb6087d53c7",
"lessThan": "3638aa1c7d87c0ca0aef23cf58cae2c48e7daca4",
"versionType": "git"
},
{
"status": "affected",
"version": "a1177825719ccef3f76ef39bbfd5ebb6087d53c7",
"lessThan": "f34ab95162763cd7352f46df169296eec28b688d",
"versionType": "git"
},
{
"status": "affected",
"version": "a1177825719ccef3f76ef39bbfd5ebb6087d53c7",
"lessThan": "533c60a0b97cee5daab376933f486207e6680fb7",
"versionType": "git"
},
{
"status": "affected",
"version": "a1177825719ccef3f76ef39bbfd5ebb6087d53c7",
"lessThan": "4a657319cfabd6199fd0b7b65bbebf6ded7a11c1",
"versionType": "git"
},
{
"status": "affected",
"version": "a1177825719ccef3f76ef39bbfd5ebb6087d53c7",
"lessThan": "bb420e8afc854d2a1caaa23a0c129839acfb7888",
"versionType": "git"
},
{
"status": "affected",
"version": "a1177825719ccef3f76ef39bbfd5ebb6087d53c7",
"lessThan": "f9c1f248607d5546075d3f731e7607d5571f2b60",
"versionType": "git"
}
],
"programFiles": [
"fs/ext4/super.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3.6"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.6",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "4.9.331",
"versionType": "semver",
"lessThanOrEqual": "4.9.*"
},
{
"status": "unaffected",
"version": "4.14.296",
"versionType": "semver",
"lessThanOrEqual": "4.14.*"
},
{
"status": "unaffected",
"version": "4.19.262",
"versionType": "semver",
"lessThanOrEqual": "4.19.*"
},
{
"status": "unaffected",
"version": "5.4.220",
"versionType": "semver",
"lessThanOrEqual": "5.4.*"
},
{
"status": "unaffected",
"version": "5.10.150",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.75",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "5.19.17",
"versionType": "semver",
"lessThanOrEqual": "5.19.*"
},
{
"status": "unaffected",
"version": "6.0.3",
"versionType": "semver",
"lessThanOrEqual": "6.0.*"
},
{
"status": "unaffected",
"version": "6.1",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/ext4/super.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2025-09-16T17:15:34.070",
"references": [
{
"url": "https://git.kernel.org/stable/c/3638aa1c7d87c0ca0aef23cf58cae2c48e7daca4",
"tags": [
"Patch"
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/4a657319cfabd6199fd0b7b65bbebf6ded7a11c1",
"tags": [
"Patch"
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/533c60a0b97cee5daab376933f486207e6680fb7",
"tags": [
"Patch"
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/947264e00c46de19a016fd81218118c708fed2f3",
"tags": [
"Patch"
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/bb420e8afc854d2a1caaa23a0c129839acfb7888",
"tags": [
"Patch"
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/dc451578446afd03c0c21913993c08898a691435",
"tags": [
"Patch"
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/f34ab95162763cd7352f46df169296eec28b688d",
"tags": [
"Patch"
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/f4b5ff0b794aa94afac7269c494550ca2f66511b",
"tags": [
"Patch"
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/f9c1f248607d5546075d3f731e7607d5571f2b60",
"tags": [
"Patch"
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Modified",
"weaknesses": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"description": [
{
"lang": "en",
"value": "CWE-476"
}
]
},
{
"type": "Secondary",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"description": [
{
"lang": "en",
"value": "CWE-476"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix null-ptr-deref in ext4_write_info\n\nI caught a null-ptr-deref bug as follows:\n==================================================================\nKASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f]\nCPU: 1 PID: 1589 Comm: umount Not tainted 5.10.0-02219-dirty #339\nRIP: 0010:ext4_write_info+0x53/0x1b0\n[...]\nCall Trace:\n dquot_writeback_dquots+0x341/0x9a0\n ext4_sync_fs+0x19e/0x800\n __sync_filesystem+0x83/0x100\n sync_filesystem+0x89/0xf0\n generic_shutdown_super+0x79/0x3e0\n kill_block_super+0xa1/0x110\n deactivate_locked_super+0xac/0x130\n deactivate_super+0xb6/0xd0\n cleanup_mnt+0x289/0x400\n __cleanup_mnt+0x16/0x20\n task_work_run+0x11c/0x1c0\n exit_to_user_mode_prepare+0x203/0x210\n syscall_exit_to_user_mode+0x5b/0x3a0\n do_syscall_64+0x59/0x70\n entry_SYSCALL_64_after_hwframe+0x44/0xa9\n ==================================================================\n\nAbove issue may happen as follows:\n-------------------------------------\nexit_to_user_mode_prepare\n task_work_run\n __cleanup_mnt\n cleanup_mnt\n deactivate_super\n deactivate_locked_super\n kill_block_super\n generic_shutdown_super\n shrink_dcache_for_umount\n dentry = sb->s_root\n sb->s_root = NULL <--- Here set NULL\n sync_filesystem\n __sync_filesystem\n sb->s_op->sync_fs > ext4_sync_fs\n dquot_writeback_dquots\n sb->dq_op->write_info > ext4_write_info\n ext4_journal_start(d_inode(sb->s_root), EXT4_HT_QUOTA, 2)\n d_inode(sb->s_root)\n s_root->d_inode <--- Null pointer dereference\n\nTo solve this problem, we use ext4_journal_start_sb directly\nto avoid s_root being used."
}
],
"lastModified": "2026-06-17T05:23:16.823",
"configurations": [
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "F5B7C986-E6CA-41ED-A833-EA73FCF421D4",
"versionEndExcluding": "4.9.331"
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "1927ABC6-E0D2-478F-B103-B982A42D1158",
"versionEndExcluding": "4.14.296",
"versionStartIncluding": "4.10"
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "D6B62970-1FAD-4ED6-930A-23E26A8D2E08",
"versionEndExcluding": "4.19.262",
"versionStartIncluding": "4.15"
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "125F7133-B3B7-4175-8CF3-FF0845483254",
"versionEndExcluding": "5.4.220",
"versionStartIncluding": "4.20"
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "C495821C-2A71-4F09-BED8-6A6EB4C9BA27",
"versionEndExcluding": "5.10.150",
"versionStartIncluding": "5.5"
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "6D945F46-F32F-4C09-8400-C3477E22A9FB",
"versionEndExcluding": "5.15.75",
"versionStartIncluding": "5.11"
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "19B4C3A4-E5C3-41DC-BB14-BE72858E7D35",
"versionEndExcluding": "5.19.17",
"versionStartIncluding": "5.16"
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "5BCD8201-B847-4442-B894-70D430128DEF",
"versionEndExcluding": "6.0.3",
"versionStartIncluding": "6.0"
}
],
"operator": "OR"
}
]
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}