CVE-2026-89490
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix readdir position truncation on 32-bit kernels In ocfs2_dir_foreach_blk_el(), the directory cookie position is rebuilt with ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1)) | offset; `ctx->pos` is loff_t (signed 64-bit), while `sb->s_blocksize` is unsigned long. On 32-bit kernels unsigned long is 32-bit, so the mask ~(sb->s_blocksize - 1) is computed as a 32-bit unsigned value (e.g. 0xfffff000 for a 4 KiB block size). In the AND expression with the 64-bit `ctx->pos`, that unsigned operand is zero-extended to 64 bits per the usual arithmetic conversions, yielding 0x00000000fffff000. The high 32 bits of `ctx->pos` are silently cleared, even though directory size is allowed to exceed 4 GiB. When readdir() crosses the 4 GiB boundary on a 32-bit kernel the position is reset back into the first 4 GiB block, making the re-validation path re-enumerate already-returned dirents indefinitely. This is ocfs2_dir_foreach_blk_el(), the extent-list readdir path taken for all non-inline directories, so a directory large enough to cross 4 GiB reaches it. This is the same class of bug that commit 3dce5bb82c97 ("exfat: Fix bitwise operation having different size") fixed in exfat, and the fix mirrors the equivalent ext4 fix in this series. Cast the operand to loff_t so the mask is 64-bit before the AND: ctx->pos = (ctx->pos & ~((loff_t)sb->s_blocksize - 1)) | offset; 64-bit kernels are unaffected.
View original CVE JSON
{
"id": "CVE-2026-89490",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-09-11T20:19:30.810",
"lastModified": "2026-10-19T09:17:42.793",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: fix readdir position truncation on 32-bit kernels\n\nIn ocfs2_dir_foreach_blk_el(), the directory cookie position is\nrebuilt with\n\n\tctx->pos = (ctx->pos & ~(sb->s_blocksize - 1)) | offset;\n\n`ctx->pos` is loff_t (signed 64-bit), while `sb->s_blocksize` is\nunsigned long. On 32-bit kernels unsigned long is 32-bit, so the mask\n\n\t~(sb->s_blocksize - 1)\n\nis computed as a 32-bit unsigned value (e.g. 0xfffff000 for a 4 KiB\nblock size). In the AND expression with the 64-bit `ctx->pos`, that\nunsigned operand is zero-extended to 64 bits per the usual arithmetic\nconversions, yielding 0x00000000fffff000. The high 32 bits of\n`ctx->pos` are silently cleared, even though directory size is\nallowed to exceed 4 GiB.\n\nWhen readdir() crosses the 4 GiB boundary on a 32-bit kernel the\nposition is reset back into the first 4 GiB block, making the\nre-validation path re-enumerate already-returned dirents indefinitely.\n\nThis is ocfs2_dir_foreach_blk_el(), the extent-list readdir path taken\nfor all non-inline directories, so a directory large enough to cross\n4 GiB reaches it.\n\nThis is the same class of bug that commit 3dce5bb82c97 (\"exfat: Fix\nbitwise operation having different size\") fixed in exfat, and the\nfix mirrors the equivalent ext4 fix in this series. Cast the operand\nto loff_t so the mask is 64-bit before the AND:\n\n\tctx->pos = (ctx->pos & ~((loff_t)sb->s_blocksize - 1)) | offset;\n\n64-bit kernels are unaffected."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"fs/ocfs2/dir.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "ccd979bdbce9fba8412beb3f1de68a9d0171b12c",
"lessThan": "c28dc3407937aa8f225942538cd585c9b28ea65a",
"versionType": "git",
"status": "affected"
},
{
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"status": "affected"
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},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"fs/ocfs2/dir.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "2.6.16",
"status": "affected"
},
{
"version": "0",
"lessThan": "2.6.16",
"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": {},
"references": [
{
"url": "https://git.kernel.org/stable/c/1001fb3b69a11eaa0dc7c7428f6edfa48b88997a",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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}