CVE-2026-46124
Description
In the Linux kernel, the following vulnerability has been resolved: isofs: validate block number from NFS file handle in isofs_export_iget isofs_fh_to_dentry() and isofs_fh_to_parent() pass an attacker- controlled block number (ifid->block or ifid->parent_block) from the NFS file handle to isofs_export_iget(), which only rejects block == 0 before calling isofs_iget() and ultimately sb_bread(). A crafted file handle with fh_len sufficient to pass the check added by commit 0405d4b63d08 ("isofs: Prevent the use of too small fid") can still drive the server to read any in-range block on the backing device as if it were an iso_directory_record. That earlier fix was assigned CVE-2025-37780. sb_bread() on an out-of-range block returns NULL cleanly via the EIO path, so there is no memory-safety violation. For in-range reads of adjacent-partition data on the same block device, the unrelated bytes end up in iso_inode_info fields that reach the NFS client as dentry metadata. The deployment surface (isofs exported over NFS from loop-mounted images) is narrow and requires an authenticated NFS peer, but the malformed-file-handle class is reportable as hardening next to the existing CVE-2025-37780 fix. Reject block >= ISOFS_SB(sb)->s_nzones in isofs_export_iget() so the check covers both isofs_fh_to_dentry() and isofs_fh_to_parent() call sites with a single line.
How to fix
- linux linux_kernel5.5, 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88, 6.15, 6.18.30, 7.0.7 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linux linux_kernel | 5.4.293 ≤ v < 5.5, 5.10.237 ≤ v < 5.10.258, 5.15.181 ≤ v < 5.15.209, 6.1.135 ≤ v < 6.1.175, 6.6.88 ≤ v < 6.6.140, 6.12.25 ≤ v < 6.12.88, 6.14.4 ≤ v < 6.15, 6.15.1 ≤ v < 6.18.30, 6.19 ≤ v < 7.0.7, 6.15, 7.1 | 5.5, 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88, 6.15, 6.18.30, 7.0.7 |
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