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CVE-2026-89782

HIGHCVSS 8.4/10EPSS 0.21%

Last modified

CVE-2026-89782 is a high-severity vulnerability rated 8.4/10 on the CVSS scale. In 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. EPSS estimates a 0.21% chance of exploitation in the next 30 days.

Description

In 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.

Metrics

CVSS 3.1
8.4/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.21%

10.8th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= b46acd6a6a627d876898e1c84d3f84902264b445, < caa0ec3fc44a13d7c21d78e4722f4f05f87ccf56; >= b46acd6a6a627d876898e1c84d3f84902264b445, < 339e59996ff193adcf1c438cf05f19e753beb3a7; >= b46acd6a6a627d876898e1c84d3f84902264b445, < ecde45cd81dc28f5696c312c5ce5a509962e9ab1; >= b46acd6a6a627d876898e1c84d3f84902264b445, < be218a01aadffe33ed4fc73e25276d676ebbd09d; >= b46acd6a6a627d876898e1c84d3f84902264b445, < aad605a450611e2a7b7cf9dd5724004d39192bfb; >= b46acd6a6a627d876898e1c84d3f84902264b445, < 967a5ff8a614d10126b6d46db1ac040948d6cb42; >= b46acd6a6a627d876898e1c84d3f84902264b445, < 111f8d74a19d85942ecbb3aba78f6f3c88e59391
LinuxLinux5.15

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-89782?
In 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.
How severe is CVE-2026-89782?
CVE-2026-89782 has a CVSS score of 8.4/10 (HIGH severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.
How do I fix CVE-2026-89782?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST