CVE-2025-38415

Advisory lineage Upstream: 0 Downstream: 72
Analyzed
Published: 25 Jul 2025, 13:32
Last modified:11 May 2026, 21:27

Vulnerability Summary

Overall Risk (default)
medium
31/100
CVSS Score
7.8 HIGH
v3.1 (nvd)
EPSS Score
0.09% LOW
0% probability +0.07%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

25 Jul 2025, 13:32
Published
Vulnerability first disclosed
11 May 2026, 21:27
Last Modified
Vulnerability information updated

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 Metrics

  • v3.1•HIGH•Score: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Trends

Current EPSS score: 0.09%• Percentile: 26%

Techniques & Countermeasures

  • CWE-787•Out-of-bounds Write

    The product writes data past the end, or before the beginning, of the intended buffer.

Affected Systems

  • debian•debian_linux

    11.0

  • linux•linux

    ≥ 0aa666190509ffab81c202c5095a166be23961ac, < db7096ea160e40d78c67fce52e7cc51bde049497 | ≥ 0aa666190509ffab81c202c5095a166be23961ac, < 549f9e3d7b60d53808c98b9fde49b4f46d0524a5 | ≥ 0aa666190509ffab81c202c5095a166be23961ac, < 5c51aa862cbeed2f3887f0382a2708956710bd68 | ≥ 0aa666190509ffab81c202c5095a166be23961ac, < 6abf6b78c6fb112eee495f5636ffcc350dd2ce25 | ≥ 0aa666190509ffab81c202c5095a166be23961ac, < 4f99357dadbf9c979ad737156ad4c37fadf7c56b | ≥ 0aa666190509ffab81c202c5095a166be23961ac, < 0aff95d9bc7fb5400ca8af507429c4b067bdb425 | ≥ 0aa666190509ffab81c202c5095a166be23961ac, < 295ab18c2dbce8d0ac6ecf7c5187e16e1ac8b282 | ≥ 0aa666190509ffab81c202c5095a166be23961ac, < 734aa85390ea693bb7eaf2240623d41b03705c84 | 2.6.29

  • linux•linux_kernel

    ≥ 2.6.29, < 5.4.295 | ≥ 5.5, < 5.10.239 | ≥ 5.11, < 5.15.186 | ≥ 5.16, < 6.1.142 | ≥ 6.2, < 6.6.94 | ≥ 6.7, < 6.12.34 | ≥ 6.13, < 6.15.3

References (10)