CVE-2025-38415

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Source
https://cve.org/CVERecord?id=CVE-2025-38415
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-38415.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2025-38415
Downstream
Related
Published
2025-07-25T13:32:09.711Z
Modified
2026-03-12T02:18:30.216460Z
Summary
Squashfs: check return result of sb_min_blocksize
Details

In the Linux kernel, the following vulnerability has been resolved:

Squashfs: check return result of sbminblocksize

Syzkaller reports an "UBSAN: shift-out-of-bounds in squashfsbioread" bug.

Syzkaller forks multiple processes which after mounting the Squashfs filesystem, issues an ioctl("/dev/loop0", LOOPSETBLOCKSIZE, 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 squashfsfill_super() fails.

msblk->devblksize = sbminblocksize(sb, SQUASHFSDEVBLKSIZE);

msblk->devblksize_log2 = ffz(~msblk->devblksize);

sbminblocksize() 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 sbminblocksize().

Database specific 
{
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38415.json"
}
References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
0aa666190509ffab81c202c5095a166be23961ac
Fixed
db7096ea160e40d78c67fce52e7cc51bde049497
Fixed
549f9e3d7b60d53808c98b9fde49b4f46d0524a5
Fixed
5c51aa862cbeed2f3887f0382a2708956710bd68
Fixed
6abf6b78c6fb112eee495f5636ffcc350dd2ce25
Fixed
4f99357dadbf9c979ad737156ad4c37fadf7c56b
Fixed
0aff95d9bc7fb5400ca8af507429c4b067bdb425
Fixed
295ab18c2dbce8d0ac6ecf7c5187e16e1ac8b282
Fixed
734aa85390ea693bb7eaf2240623d41b03705c84

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-38415.json"