Squashfs: fix uninit-value in squashfs_get_parent
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 5 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 2.6.29 and later | 5.4.301, 5.10.246, 5.15.195, 6.1.156, 6.6.112, 6.12.53, 6.17.3, 6.18 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.29 and later Fixed in 5.4.301, 5.10.246, 5.15.195, 6.1.156, 6.6.112, 6.12.53, 6.17.3, 6.18 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.4.301, 5.10.246, 5.15.195, 6.1.156, 6.6.112, 6.12.53, 6.17.3, 6.18
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2025-40049
- 2026-10-03 Alias added: GHSA-pq9p-38r9-fjq5
References
Other 8
- https://git.kernel.org/stable/c/f81a5bc9e924ee1950e0dd82bd10749048390f6e
- https://git.kernel.org/stable/c/382a47fae449e554ef1e8c198667fd2f3270b945
- https://git.kernel.org/stable/c/61d38b5ce2782bff3cacaacbb8164087a73ed1a5
- https://git.kernel.org/stable/c/81a2bca52d43fc9d9abf07408b91255131c5dc53
- https://git.kernel.org/stable/c/c28b0ca029edf5d0558abcd76cb8c732706cd339
- https://git.kernel.org/stable/c/1b3ccd0019132880c94bb00ca7088c1749308f82
- https://git.kernel.org/stable/c/91b99db7a92e57ff48a96a1b10fddfd2547e7f53
- https://git.kernel.org/stable/c/74058c0a9fc8b2b4d5f4a0ef7ee2cfa66a9e49cf
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Sources
- CVE-2025-40049 · CVE Program
- CVE-2025-40049 · NVD
- FIRST EPSS
- GHSA-pq9p-38r9-fjq5 · GitHub Advisory Database · CC BY 4.0
- CVE-2025-40049 · Red Hat security data · CC BY 4.0
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