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CVE-2025-38415

Squashfs: check return result of sb_min_blocksize

At a glance

Severity
Not available
EPSS
EPSS 0.22 % · percentile 12 (2026-10-27)
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Analyzed

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().

Scores

VersionScoreVectorScored by
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · nvd@nist.gov (Primary)

Weaknesses (CWE)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
Linux · Linuxaffected 0aa666190509ffab81c202c5095a166be23961ac < db7096ea160e40d78c67fce52e7cc51bde049497 ; affected 0aa666190509ffab81c202c5095a166be23961ac < 549f9e3d7b60d53808c98b9fde49b4f46d0524a5 ; affected 0aa666190509ffab81c202c5095a166be23961ac < 5c51aa862cbeed2f3887f0382a2708956710bd68 ; affected 0aa666190509ffab81c202c5095a166be23961ac < 6abf6b78c6fb112eee495f5636ffcc350dd2ce25 ; affected 0aa666190509ffab81c202c5095a166be23961ac < 4f99357dadbf9c979ad737156ad4c37fadf7c56b ; affected 0aa666190509ffab81c202c5095a166be23961ac < 0aff95d9bc7fb5400ca8af507429c4b067bdb425
Linux · Linuxaffected 2.6.29 ; unaffected 0 < 2.6.29 ; unaffected 5.4.295 ≤ 5.4.* ; unaffected 5.10.239 ≤ 5.10.* ; unaffected 5.15.186 ≤ 5.15.* ; unaffected 6.1.142 ≤ 6.1.*

References

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD