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 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.

CVSS

No CVSS.

References

Link	Resource
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

Configurations

No configuration.

History

No history.

Information

Published : 2025-10-28 12:15

Updated : 2026-06-17 09:21

NVD link : CVE-2025-40049

Mitre link : CVE-2025-40049

CVE.ORG link : CVE-2025-40049

JSON object : View

Products Affected

No product.

CWE

No CWE.

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In particular the inode number\nis that of a symbolic link, rather than a directory.\n\nSquashfs_get_parent() gets called with that symbolic link inode, and\naccesses the parent member field.\n\n\tunsigned int parent_ino = squashfs_i(inode)->parent;\n\nBecause non-directory inodes in Squashfs do not have a parent value, this\nis uninitialised, and this causes an uninitialised value access.\n\nThe fix is to initialise parent with the invalid inode 0, which will cause\nan EINVAL error to be returned.\n\nRegular inodes used to share the parent field with the block_list_start\nfield. This is removed in this commit to enable the parent field to\ncontain the invalid inode number 0."}], "lastModified": "2026-06-17T09:21:10.903", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}