Strix
64K

CVE-2026-89786

CRITICALCVSS 9.1/10EPSS 0.21%

Last modified

CVE-2026-89786 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. 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. EPSS estimates a 0.21% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
9.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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>= c4d8b0235aa98f8c26bf94d308be3fdd24154572, < d1e7c186555ad65554fd2f2b02f5a539aa35ae48; >= c4d8b0235aa98f8c26bf94d308be3fdd24154572, < 5fd20d4e50dd6e460b3ea8e4396f8553d4526f8f; >= c4d8b0235aa98f8c26bf94d308be3fdd24154572, < 1a1dea633b724a1c042dbcdb1fed27f410916688; >= c4d8b0235aa98f8c26bf94d308be3fdd24154572, < b060861f662d4826dc700a1c3584243bb3474cfe; >= c4d8b0235aa98f8c26bf94d308be3fdd24154572, < 6702c7da86d8cdb88d0fc57166286e115ffeb8c0; >= c4d8b0235aa98f8c26bf94d308be3fdd24154572, < 36bf17bb90cdf7a623499b624b05acde4d2feef5; >= c4d8b0235aa98f8c26bf94d308be3fdd24154572, < 9333cc809f0a89e001b814155a6cb8903a6274df
LinuxLinux3.10

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-89786?
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.
How severe is CVE-2026-89786?
CVE-2026-89786 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.
How do I fix CVE-2026-89786?
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.

How Strix Helps

Related CVEs from 2026

View all 2026CVEs →

Are you affected by CVE-2026-89786?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST