Vulnerability Description
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.
References
- https://git.kernel.org/stable/c/1b3ccd0019132880c94bb00ca7088c1749308f82
- https://git.kernel.org/stable/c/382a47fae449e554ef1e8c198667fd2f3270b945
- https://git.kernel.org/stable/c/61d38b5ce2782bff3cacaacbb8164087a73ed1a5
- https://git.kernel.org/stable/c/74058c0a9fc8b2b4d5f4a0ef7ee2cfa66a9e49cf
- https://git.kernel.org/stable/c/81a2bca52d43fc9d9abf07408b91255131c5dc53
- https://git.kernel.org/stable/c/91b99db7a92e57ff48a96a1b10fddfd2547e7f53
- https://git.kernel.org/stable/c/c28b0ca029edf5d0558abcd76cb8c732706cd339
- https://git.kernel.org/stable/c/f81a5bc9e924ee1950e0dd82bd10749048390f6e
FAQ
What is CVE-2025-40049?
CVE-2025-40049 is a documented vulnerability. 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 c...
How severe is CVE-2025-40049?
CVSS scoring is not yet available for CVE-2025-40049. Check NVD for updates.
Is there a patch for CVE-2025-40049?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.