In the Linux kernel, the following vulnerability has been resolved:
ext4: fix out-of-bounds read in ext4_read_inline_dir()
ext4_read_inline_dir() can read a dirent header past the end of its inline
buffer, triggering a slab-out-of-bounds read during getdents64():
BUG: KASAN: slab-out-of-bounds in __ext4_check_dir_entry
Read of size 2 at addr ffff88800f3dd23c by task exploit/148
...
__ext4_check_dir_entry
ext4_read_inline_dir
iterate_dir
The dirent payload lives in a buffer of exactly inline_size bytes:
dir_buf = kmalloc(inline_size, GFP_NOFS);
but iteration runs in a position space extra_offset bytes larger
(extra_size = extra_offset + inline_size) so the synthetic "." and ".."
land at their block-dir offsets. A dirent is formed at "dir_buf + pos -
extra_offset", yet the ext4_check_dir_entry() length argument uses the
larger extra_size. A position whose dirent header would extend past
extra_size is therefore accepted, and the rescan loop's rec_len probe and
ext4_check_dir_entry() dereference de->rec_len before the entry is rejected.
Reject a position whose minimum-size dirent header would not fit within
extra_size before forming de, in both the rescan and main loops, and pass
inline_size rather than extra_size to ext4_check_dir_entry() so the length
check matches the physical buffer.
ext4: fix out-of-bounds read in ext4_read_inline_dir()
ext4_read_inline_dir() can read a dirent header past the end of its inline
buffer, triggering a slab-out-of-bounds read during getdents64():
BUG: KASAN: slab-out-of-bounds in __ext4_check_dir_entry
Read of size 2 at addr ffff88800f3dd23c by task exploit/148
...
__ext4_check_dir_entry
ext4_read_inline_dir
iterate_dir
The dirent payload lives in a buffer of exactly inline_size bytes:
dir_buf = kmalloc(inline_size, GFP_NOFS);
but iteration runs in a position space extra_offset bytes larger
(extra_size = extra_offset + inline_size) so the synthetic "." and ".."
land at their block-dir offsets. A dirent is formed at "dir_buf + pos -
extra_offset", yet the ext4_check_dir_entry() length argument uses the
larger extra_size. A position whose dirent header would extend past
extra_size is therefore accepted, and the rescan loop's rec_len probe and
ext4_check_dir_entry() dereference de->rec_len before the entry is rejected.
Reject a position whose minimum-size dirent header would not fit within
extra_size before forming de, in both the rescan and main loops, and pass
inline_size rather than extra_size to ext4_check_dir_entry() so the length
check matches the physical buffer.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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Advisories
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Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Wed, 16 Sep 2026 09:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: ext4: fix out-of-bounds read in ext4_read_inline_dir() ext4_read_inline_dir() can read a dirent header past the end of its inline buffer, triggering a slab-out-of-bounds read during getdents64(): BUG: KASAN: slab-out-of-bounds in __ext4_check_dir_entry Read of size 2 at addr ffff88800f3dd23c by task exploit/148 ... __ext4_check_dir_entry ext4_read_inline_dir iterate_dir The dirent payload lives in a buffer of exactly inline_size bytes: dir_buf = kmalloc(inline_size, GFP_NOFS); but iteration runs in a position space extra_offset bytes larger (extra_size = extra_offset + inline_size) so the synthetic "." and ".." land at their block-dir offsets. A dirent is formed at "dir_buf + pos - extra_offset", yet the ext4_check_dir_entry() length argument uses the larger extra_size. A position whose dirent header would extend past extra_size is therefore accepted, and the rescan loop's rec_len probe and ext4_check_dir_entry() dereference de->rec_len before the entry is rejected. Reject a position whose minimum-size dirent header would not fit within extra_size before forming de, in both the rescan and main loops, and pass inline_size rather than extra_size to ext4_check_dir_entry() so the length check matches the physical buffer. | |
| Title | ext4: fix out-of-bounds read in ext4_read_inline_dir() | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-16T08:48:23.730Z
Reserved: 2026-09-11T19:38:34.766Z
Link: CVE-2026-89786
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-16T09:17:09.330
Modified: 2026-09-16T09:17:09.330
Link: CVE-2026-89786
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.