CVE-2025-38415

HIGH EPSS 7.9%
Published Jul 25, 202511mo ago · Modified Jun 18, 20261w ago
7.8 CVSS 3.1
High
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Published Jul 25, 2025 11mo ago
Last Modified Jun 18, 2026 1w ago

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().

CVSS Details

Base Score
7.8
Exploitability
1.8
Impact
5.9
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
7.9% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-787 Out-of-bounds Write Memory Safety

Affected Products 8

VendorProductVersionRange
linuxlinux_kernel*≥2.6.29  –  <5.4.295
linuxlinux_kernel*≥5.5  –  <5.10.239
linuxlinux_kernel*≥5.11  –  <5.15.186
linuxlinux_kernel*≥5.16  –  <6.1.142
linuxlinux_kernel*≥6.2  –  <6.6.94
linuxlinux_kernel*≥6.7  –  <6.12.34
linuxlinux_kernel*≥6.13  –  <6.15.3
debiandebian_linux11.0any

References 10

  • git.kernel.org https://git.kernel.org/stable/c/0aff95d9bc7fb5400ca8af507429c4b067bdb425
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/295ab18c2dbce8d0ac6ecf7c5187e16e1ac8b282
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/4f99357dadbf9c979ad737156ad4c37fadf7c56b
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/549f9e3d7b60d53808c98b9fde49b4f46d0524a5
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/5c51aa862cbeed2f3887f0382a2708956710bd68
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/6abf6b78c6fb112eee495f5636ffcc350dd2ce25
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/734aa85390ea693bb7eaf2240623d41b03705c84
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/db7096ea160e40d78c67fce52e7cc51bde049497
    Patch
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
    Mailing ListThird Party Advisory
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
    Mailing ListThird Party Advisory

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/0aff95d9bc7fb5400ca8af507429c4b067bdb425
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/295ab18c2dbce8d0ac6ecf7c5187e16e1ac8b282
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/4f99357dadbf9c979ad737156ad4c37fadf7c56b
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/549f9e3d7b60d53808c98b9fde49b4f46d0524a5
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/5c51aa862cbeed2f3887f0382a2708956710bd68
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/6abf6b78c6fb112eee495f5636ffcc350dd2ce25
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/734aa85390ea693bb7eaf2240623d41b03705c84
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/db7096ea160e40d78c67fce52e7cc51bde049497
    Patch