CVE-2026-90203

high

Description

In the Linux kernel, the following vulnerability has been resolved: Squashfs: check block offset is not negative If a negative offset is read off disk (for example the offset into the decompressed fragment block), this will cause squashfs_copy_data() to perform an out of bounds access. Fix by checking if offset is negative, and returning 0. This matches existing behaviour where an offset beyond the block returns 0 bytes copied. To trigger this out of bounds access requires a crafted Squashfs filesystem and CAP_SYS_ADMIN to mount it. Unprivileged users will not be able to mount such a filesystem, but once mounted, an unprivileged user can trigger the out of bounds access by reading the crafted file with the negative offset.

References

https://git.kernel.org/stable/c/e4afd90bc7bf3dd477970c6c42bdd29ad3fda7fe

https://git.kernel.org/stable/c/e300eb5002925b29be803d2661af07266cfa267e

https://git.kernel.org/stable/c/d0a3729d464fcf516416a41cf304c0c92126ee03

https://git.kernel.org/stable/c/c2a126fca820ae74872da28de68dc74d4595dc4b

https://git.kernel.org/stable/c/bbb2218eb072b0a15dc063929200183bd23c2344

https://git.kernel.org/stable/c/b169185d5c672b989985c6c2e38cafab2548ba88

https://git.kernel.org/stable/c/95dadf366c117dcdca78a570e6832071deab1ecd

https://git.kernel.org/stable/c/3d2f0cb66c909ea2312cdef465165bb9a3ba2d84

Details

Source: Mitre, NVD

Published: 2026-09-17

Updated: 2026-09-18

Risk Information

CVSS v2

Base Score: 6.6

Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:N/A:C

Severity: Medium

CVSS v3

Base Score: 7.1

Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H

Severity: High

EPSS

EPSS: 0.00211