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CVE-2026-90203

HIGHCVSS 7.1/10

Last modified

CVE-2026-90203 is a high-severity vulnerability rated 7.1/10 on the CVSS scale. 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.

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.

Metrics

CVSS 3.1
7.1/10

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

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= f400e12656ab518be107febfe2315fb1eab5a342, < b169185d5c672b989985c6c2e38cafab2548ba88; >= f400e12656ab518be107febfe2315fb1eab5a342, < c2a126fca820ae74872da28de68dc74d4595dc4b; >= f400e12656ab518be107febfe2315fb1eab5a342, < 95dadf366c117dcdca78a570e6832071deab1ecd; >= f400e12656ab518be107febfe2315fb1eab5a342, < 3d2f0cb66c909ea2312cdef465165bb9a3ba2d84; >= f400e12656ab518be107febfe2315fb1eab5a342, < bbb2218eb072b0a15dc063929200183bd23c2344; >= f400e12656ab518be107febfe2315fb1eab5a342, < d0a3729d464fcf516416a41cf304c0c92126ee03; >= f400e12656ab518be107febfe2315fb1eab5a342, < e4afd90bc7bf3dd477970c6c42bdd29ad3fda7fe; >= f400e12656ab518be107febfe2315fb1eab5a342, < e300eb5002925b29be803d2661af07266cfa267e
LinuxLinux2.6.29

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-90203?
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.
How severe is CVE-2026-90203?
CVE-2026-90203 has a CVSS score of 7.1/10 (HIGH severity).
How do I fix CVE-2026-90203?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST