CVE-2025-40049

  • Published: 1761653739
  • Last modified: 1761747353

CVE-2025-40049 — In the Linux kernel, the following vulnerability has been resolved: Squashfs: fix uninit-value in squashfs_get_parent Syzkaller reports a "KMSAN: uninit-value in squashfs_get_parent" bug. This is caused by open_by_handle_at() being called with a file handle containing an invalid parent inode number. In particular the inode number is that of a symbolic…

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In the Linux kernel, the following vulnerability has been resolved:

Squashfs: fix uninit-value in squashfs_get_parent

Syzkaller reports a “KMSAN: uninit-value in squashfs_get_parent” bug.

This is caused by open_by_handle_at() being called with a file handle
containing an invalid parent inode number. In particular the inode number
is that of a symbolic link, rather than a directory.

Squashfs_get_parent() gets called with that symbolic link inode, and
accesses the parent member field.

unsigned int parent_ino = squashfs_i(inode)->parent;

Because non-directory inodes in Squashfs do not have a parent value, this
is uninitialised, and this causes an uninitialised value access.

The fix is to initialise parent with the invalid inode 0, which will cause
an EINVAL error to be returned.

Regular inodes used to share the parent field with the block_list_start
field. This is removed in this commit to enable the parent field to
contain the invalid inode number 0.

🧠 Explainer: What this vulnerability means

Summary: the product from the vendor is impacted (CWE: unspecified).

Impact: Systems could be compromised, leading to confidentiality, integrity, or availability loss.

Mitigation: Upgrade immediately to the remediated release and follow vendor hardening guidance.

No vendor/product data yet.

No explicit mitigation/advisory links found in references.