CVE-2025-38415

CVE Details

Release Date:2025-07-25
Impact:Moderate What is this?

Description


In the Linux kernel, the following vulnerability has been resolved: Squashfs: check return result of sb_min_blocksize Syzkaller reports an "UBSAN: shift-out-of-bounds in squashfs_bio_read" bug. Syzkaller forks multiple processes which after mounting the Squashfs filesystem, issues an ioctl("/dev/loop0", LOOP_SET_BLOCK_SIZE, 0x8000). Now if this ioctl occurs at the same time another process is in the process of mounting a Squashfs filesystem on /dev/loop0, the failure occurs. When this happens the following code in squashfs_fill_super() fails. ---- msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE); msblk->devblksize_log2 = ffz(~msblk->devblksize); ---- sb_min_blocksize() returns 0, which means msblk->devblksize is set to 0. As a result, ffz(~msblk->devblksize) returns 64, and msblk->devblksize_log2 is set to 64. This subsequently causes the UBSAN: shift-out-of-bounds in fs/squashfs/block.c:195:36 shift exponent 64 is too large for 64-bit type 'u64' (aka 'unsigned long long') This commit adds a check for a 0 return by sb_min_blocksize().

See more information about CVE-2025-38415 from MITRE CVE dictionary and NIST NVD


NOTE: The following CVSS metrics and score provided are preliminary and subject to review.


CVSS v3 metrics

Base Score: 7.0
Vector String: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Version: 3.1
Attack Vector: Local
Attack Complexity: High
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality Impact: High
Integrity Impact: High
Availability Impact: High

Errata information


PlatformErrataRelease Date
Oracle Linux version 10 (kernel-uek) ELSA-2025-205512025-09-08
Oracle Linux version 8 (kernel-uek) ELSA-2025-205522025-09-08
Oracle Linux version 9 (kernel-uek) ELSA-2025-205512025-09-08
Oracle Linux version 9 (kernel-uek) ELSA-2025-205522025-09-08


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