GHSA-Q8VR-48QG-6QFP
Vulnerability from github – Published: 2026-09-16 09:30 – Updated: 2026-09-16 09:30In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: reject restart table growth beyond U16_MAX entries
During $LogFile replay, log_replay() indexes the transaction table by the transact_id taken from the log record header. check_log_rec() only verifies that transact_id is non-zero and properly aligned, not its magnitude, so a crafted image can request an arbitrarily large index.
alloc_rsttbl_from_idx() grows the table to cover that index via extend_rsttbl(), which passes the new entry count to init_rsttbl():
rt = init_rsttbl(esize, used + add);
used + add is computed as u32 but init_rsttbl() takes a u16, and the count is stored in struct RESTART_TABLE as a __le16. When used + add exceeds U16_MAX it is truncated, init_rsttbl() allocates a table far smaller than the index requires, and alloc_rsttbl_from_idx() then dereferences and writes at the original, untruncated offset -- an out-of-bounds access past the allocation, reachable by mounting a crafted NTFS image.
BUG: KASAN: use-after-free in alloc_rsttbl_from_idx (fs/ntfs3/fslog.c:950) Read of size 4 at addr ffff8880327ffff8 by task exploit alloc_rsttbl_from_idx (fs/ntfs3/fslog.c:950) log_replay (fs/ntfs3/fslog.c:4562) ntfs_loadlog_and_replay (fs/ntfs3/fsntfs.c:324) ntfs_fill_super (fs/ntfs3/super.c:1393) get_tree_bdev_flags vfs_get_tree path_mount __x64_sys_mount
A restart table is limited to U16_MAX entries by its __le16 count, so a larger growth request is invalid input. Reject it in extend_rsttbl(); all callers already handle a NULL return.
{
"affected": [],
"aliases": [
"CVE-2026-89782"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-16T09:17:08Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: reject restart table growth beyond U16_MAX entries\n\nDuring $LogFile replay, log_replay() indexes the transaction table by the\ntransact_id taken from the log record header. check_log_rec() only\nverifies that transact_id is non-zero and properly aligned, not its\nmagnitude, so a crafted image can request an arbitrarily large index.\n\nalloc_rsttbl_from_idx() grows the table to cover that index via\nextend_rsttbl(), which passes the new entry count to init_rsttbl():\n\n\trt = init_rsttbl(esize, used + add);\n\nused + add is computed as u32 but init_rsttbl() takes a u16, and the\ncount is stored in struct RESTART_TABLE as a __le16. When used + add\nexceeds U16_MAX it is truncated, init_rsttbl() allocates a table far\nsmaller than the index requires, and alloc_rsttbl_from_idx() then\ndereferences and writes at the original, untruncated offset -- an\nout-of-bounds access past the allocation, reachable by mounting a\ncrafted NTFS image.\n\n BUG: KASAN: use-after-free in alloc_rsttbl_from_idx (fs/ntfs3/fslog.c:950)\n Read of size 4 at addr ffff8880327ffff8 by task exploit\n alloc_rsttbl_from_idx (fs/ntfs3/fslog.c:950)\n log_replay (fs/ntfs3/fslog.c:4562)\n ntfs_loadlog_and_replay (fs/ntfs3/fsntfs.c:324)\n ntfs_fill_super (fs/ntfs3/super.c:1393)\n get_tree_bdev_flags\n vfs_get_tree\n path_mount\n __x64_sys_mount\n\nA restart table is limited to U16_MAX entries by its __le16 count, so a\nlarger growth request is invalid input. Reject it in extend_rsttbl();\nall callers already handle a NULL return.",
"id": "GHSA-q8vr-48qg-6qfp",
"modified": "2026-09-16T09:30:30Z",
"published": "2026-09-16T09:30:30Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89782"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/111f8d74a19d85942ecbb3aba78f6f3c88e59391"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/339e59996ff193adcf1c438cf05f19e753beb3a7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/967a5ff8a614d10126b6d46db1ac040948d6cb42"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/aad605a450611e2a7b7cf9dd5724004d39192bfb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/be218a01aadffe33ed4fc73e25276d676ebbd09d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/caa0ec3fc44a13d7c21d78e4722f4f05f87ccf56"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ecde45cd81dc28f5696c312c5ce5a509962e9ab1"
}
],
"schema_version": "1.4.0",
"severity": []
}
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