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CVE-2026-46124

isofs: validate block number from NFS file handle in isofs_export_iget

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88, and 4 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: yes
  • Technical impact: partial

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: yes · Technical impact: partial

  3. Record last updated

Affected versions

  • Linux Linux

    From 5e7de55602c61c8ff28db075cc49c8dd6989d7e0 · fixed in ee0024f5a7e3c73aa253869fae9650ae054093ca; From 63d5a3e207bf315a32c7d16de6c89753a759f95a · fixed in 31dbb4ba0f719ae7774e4c0c95172c9bf81692f5; From 0fdafdaef796816a9ed0fd7ac812932d569d9beb · fixed in 908a76f0b1038035e6ebb4f2293ce079f92e0a02; From 952e7a7e317f126d0a2b879fc531b716932d5ffa · fixed in bb0988ed4f2e26d59bbb58f644cb3a55b7521e21; From 56dfffea9fd3be0b3795a9ca6401e133a8427e0b · fixed in 0a1af74ae2177bda3aee0837a0546309aa539d0d; From 0405d4b63d082861f4eaff9d39c78ee9dc34f845 · fixed in afbafeddf23db13fe2edb2d5c0bf4bbb13d7881b; From 0405d4b63d082861f4eaff9d39c78ee9dc34f845 · fixed in 4c721a1d9b3c4fcaf59cc9b2281e3ec5a043e1a6; From 0405d4b63d082861f4eaff9d39c78ee9dc34f845 · fixed in 24376458138387fb251e782e624c7776e9826796; From 5.10.237 · fixed in 5.10.258; From 5.15.181 · fixed in 5.15.209; From 6.1.135 · fixed in 6.1.175; From 6.6.88 · fixed in 6.6.140; From 6.12.25 · fixed in 6.12.88; From 5.4.293 · fixed in 5.5; From 6.14.4 · fixed in 6.15

  • Linux Linux

    6.15

  • KernelLinux

    fixed in 5.10.258; From 5.11.0 · fixed in 5.15.209; From 5.16.0 · fixed in 6.1.175; From 6.2.0 · fixed in 6.6.140; From 6.7.0 · fixed in 6.12.88; From 6.13.0 · fixed in 6.18.30; From 6.15.0 · fixed in 7.0.7

References 8

git.kernel.org