CVE Catalog

CVE-2026-90203

HighCVSS 7.1
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.17%

6th percentile - higher than 6% of all known CVEs

Summary

In the Linux kernel, the Squashfs filesystem fails to check whether a block offset read from disk is negative. A negative offset (e.g., into the decompressed fragment block) causes an out-of-bounds access in squashfs_copy_data(). The fix checks if the offset is negative and returns 0, matching existing behavior for offsets beyond the block.

Risk Assessment

An out-of-bounds access may lead to a system crash or potential code execution. It requires mounting a crafted Squashfs filesystem with CAP_SYS_ADMIN, but once mounted, an unprivileged user can trigger the bug by reading the crafted file.

Recommendation

Update the Linux kernel to a version containing the fix for this issue. Avoid mounting untrusted Squashfs images until the update is applied.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS