CVE-2026-89557
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: md: do overflow check for sb->bblog_shift in super_1_load() In super_1_load(), sb->bblog_shift is an __u8 type value loaded from on- disk superblock. It is used for badblocks API badblocks_set() by the following sequence, 1930 rdev->badblocks.shift = sb->bblog_shift; 1931 for (i = 0 ; i < (sectors << (9-3)) ; i++, bbp++) { 1932 u64 bb = le64_to_cpu(*bbp); 1933 int count = bb & (0x3ff); 1934 u64 sector = bb >> 10; 1935 sector <<= sb->bblog_shift; 1936 count <<= sb->bblog_shift; 1937 if (bb + 1 == 0) 1938 break; 1939 if (!badblocks_set(&rdev->badblocks, sector, count, 1)) 1940 return -EINVAL; 1941 } bb->bblog_shit is in range of 0-255, variable sector is 64bit width, for an invalid bb->bblog_shit, it is possible to make sector be overflowed by the following calculation, 1935 sector <<= sb->bblog_shift; Then in turn when call badblocks_set() at line 1939 with the invalid rdev->badblocks.shift set at line 1930, may result an overflow inside _badblocks_clear() in block/badblocks.c. Although there are many places to call badblocks APIs, the non-zero shift value is only used in super_1_load(), other places always use 0 as the shift value. Therefore it is unnecessary to do a general shift value overflow check inside badblock API, and just check here as the caller. This may avoid unnecessary check, make the badblocks API code more simple and elegant.
View original CVE JSON
{
"id": "CVE-2026-89557",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-09-11T20:19:39.403",
"lastModified": "2026-10-19T09:17:51.190",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmd: do overflow check for sb->bblog_shift in super_1_load()\n\nIn super_1_load(), sb->bblog_shift is an __u8 type value loaded from on-\ndisk superblock. It is used for badblocks API badblocks_set() by the\nfollowing sequence,\n\n 1930 rdev->badblocks.shift = sb->bblog_shift;\n 1931 for (i = 0 ; i < (sectors << (9-3)) ; i++, bbp++) {\n 1932 u64 bb = le64_to_cpu(*bbp);\n 1933 int count = bb & (0x3ff);\n 1934 u64 sector = bb >> 10;\n 1935 sector <<= sb->bblog_shift;\n 1936 count <<= sb->bblog_shift;\n 1937 if (bb + 1 == 0)\n 1938 break;\n 1939 if (!badblocks_set(&rdev->badblocks, sector, count, 1))\n 1940 return -EINVAL;\n 1941 }\n\nbb->bblog_shit is in range of 0-255, variable sector is 64bit width, for\nan invalid bb->bblog_shit, it is possible to make sector be overflowed\nby the following calculation,\n 1935 sector <<= sb->bblog_shift;\nThen in turn when call badblocks_set() at line 1939 with the invalid\nrdev->badblocks.shift set at line 1930, may result an overflow inside\n_badblocks_clear() in block/badblocks.c.\n\nAlthough there are many places to call badblocks APIs, the non-zero\nshift value is only used in super_1_load(), other places always use 0 as\nthe shift value. Therefore it is unnecessary to do a general shift value\noverflow check inside badblock API, and just check here as the caller.\n\nThis may avoid unnecessary check, make the badblocks API code more simple\nand elegant."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"drivers/md/md.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "2699b67223aca6b1450fc2f72e40fada952afc85",
"lessThan": "94c820d99a4305d4ded41a97ed37ec7d26c56e7f",
"versionType": "git",
"status": "affected"
},
{
"version": "2699b67223aca6b1450fc2f72e40fada952afc85",
"lessThan": "573fb68105fdc6a127ba6069e58a0d2aff3c9f93",
"versionType": "git",
"status": "affected"
},
{
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"lessThan": "323f3a056dbccb39a642ebde642044a680f3a6d6",
"versionType": "git",
"status": "affected"
},
{
"version": "2699b67223aca6b1450fc2f72e40fada952afc85",
"lessThan": "0a03f9541c06fda64301dcf94f376f07ce2cc396",
"versionType": "git",
"status": "affected"
},
{
"version": "2699b67223aca6b1450fc2f72e40fada952afc85",
"lessThan": "75d15738fd33a782606d0dc80cfeff47edf2ddd8",
"versionType": "git",
"status": "affected"
},
{
"version": "2699b67223aca6b1450fc2f72e40fada952afc85",
"lessThan": "3b097416b4cff77285c1f472fc2c4058d8a7554f",
"versionType": "git",
"status": "affected"
},
{
"version": "2699b67223aca6b1450fc2f72e40fada952afc85",
"lessThan": "df7d4d011d5ace20699ea948712f09f9ac08924f",
"versionType": "git",
"status": "affected"
},
{
"version": "2699b67223aca6b1450fc2f72e40fada952afc85",
"lessThan": "35d522bd32462afcf1981dab6da8a9256c26c1e0",
"versionType": "git",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"drivers/md/md.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "3.1",
"status": "affected"
},
{
"version": "0",
"lessThan": "3.1",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "5.10.270",
"lessThanOrEqual": "5.10.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "5.15.221",
"lessThanOrEqual": "5.15.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.1.188",
"lessThanOrEqual": "6.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.6.157",
"lessThanOrEqual": "6.6.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.109",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.50",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.2.4",
"lessThanOrEqual": "7.2.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.3",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary",
"cvssData": {
"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",
"attackVector": "LOCAL",
"attackComplexity": "LOW",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-10-16T19:24:07.440563Z",
"id": "CVE-2026-89557",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"references": [
{
"url": "https://git.kernel.org/stable/c/0a03f9541c06fda64301dcf94f376f07ce2cc396",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
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{
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{
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{
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{
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}