High 7.1Published Sep 17, 2026

CVE-2026-90203Squashfs: check block offset is not negative

Updated under an hour ago (Oct 27, 2026, 3:10 AM ET)

Does this affect you?

It affects Linux. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for Linux

Exploited in the last 30 days

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.

CVSS: 7.1 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Received
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from f400e12656ab518be107febfe2315fb1eab5a342 before b169185d5c672b989985c6c2e38cafab2548ba88; from f400e12656ab518be107febfe2315fb1eab5a342 before c2a126fca820ae74872da28de68dc74d4595dc4b; from f400e12656ab518be107febfe2315fb1eab5a342 before 95dadf366c117dcdca78a570e6832071deab1ecd; from f400e12656ab518be107febfe2315fb1eab5a342 before 3d2f0cb66c909ea2312cdef465165bb9a3ba2d84; from f400e12656ab518be107febfe2315fb1eab5a342 before bbb2218eb072b0a15dc063929200183bd23c2344; from f400e12656ab518be107febfe2315fb1eab5a342 before d0a3729d464fcf516416a41cf304c0c92126ee03; from f400e12656ab518be107febfe2315fb1eab5a342 before e4afd90bc7bf3dd477970c6c42bdd29ad3fda7fe; from f400e12656ab518be107febfe2315fb1eab5a342 before e300eb5002925b29be803d2661af07266cfa267e	CNA record

References

References

https://git.kernel.org/stable/c/b169185d5c672b989985c6c2e38cafab2548ba88
https://git.kernel.org/stable/c/c2a126fca820ae74872da28de68dc74d4595dc4b
https://git.kernel.org/stable/c/95dadf366c117dcdca78a570e6832071deab1ecd
https://git.kernel.org/stable/c/3d2f0cb66c909ea2312cdef465165bb9a3ba2d84
https://git.kernel.org/stable/c/bbb2218eb072b0a15dc063929200183bd23c2344
https://git.kernel.org/stable/c/d0a3729d464fcf516416a41cf304c0c92126ee03
https://git.kernel.org/stable/c/e4afd90bc7bf3dd477970c6c42bdd29ad3fda7fe
https://git.kernel.org/stable/c/e300eb5002925b29be803d2661af07266cfa267e

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.