CVE-2026-46124isofs: validate block number from NFS file handle in isofs_export_iget
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Undergoing Analysis
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 5e7de55602c61c8ff28db075cc49c8dd6989d7e0 before ee0024f5a7e3c73aa253869fae9650ae054093ca; 63d5a3e207bf315a32c7d16de6c89753a759f95a builds before 31dbb4ba0f719ae7774e4c0c95172c9bf81692f5; from 0fdafdaef796816a9ed0fd7ac812932d569d9beb before 908a76f0b1038035e6ebb4f2293ce079f92e0a02; from 952e7a7e317f126d0a2b879fc531b716932d5ffa before bb0988ed4f2e26d59bbb58f644cb3a55b7521e21; 56dfffea9fd3be0b3795a9ca6401e133a8427e0b builds before 0a1af74ae2177bda3aee0837a0546309aa539d0d; from 0405d4b63d082861f4eaff9d39c78ee9dc34f845 before afbafeddf23db13fe2edb2d5c0bf4bbb13d7881b; 0405d4b63d082861f4eaff9d39c78ee9dc34f845 builds before 4c721a1d9b3c4fcaf59cc9b2281e3ec5a043e1a6; from 0405d4b63d082861f4eaff9d39c78ee9dc34f845 before 24376458138387fb251e782e624c7776e9826796; and 9 more ranges | CNA record |
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name) | all versions | CISA ADP |
linux linux_kernel linux:linux_kernel | from 5.4.293 before 5.5; from 5.10.237 before 5.10.258; from 5.15.181 before 5.15.209; from 6.1.135 before 6.1.175; from 6.6.88 before 6.6.140; from 6.12.25 before 6.12.88; from 6.14.4 before 6.15; from 6.15.1 before 6.18.30; and 8 more ranges | NVD |
References
- https://git.kernel.org/stable/c/ee0024f5a7e3c73aa253869fae9650ae054093capatch
- https://git.kernel.org/stable/c/31dbb4ba0f719ae7774e4c0c95172c9bf81692f5patch
- https://git.kernel.org/stable/c/908a76f0b1038035e6ebb4f2293ce079f92e0a02patch
- https://git.kernel.org/stable/c/bb0988ed4f2e26d59bbb58f644cb3a55b7521e21patch
- https://git.kernel.org/stable/c/0a1af74ae2177bda3aee0837a0546309aa539d0dpatch
- https://git.kernel.org/stable/c/afbafeddf23db13fe2edb2d5c0bf4bbb13d7881bpatch
- https://git.kernel.org/stable/c/4c721a1d9b3c4fcaf59cc9b2281e3ec5a043e1a6patch
- https://git.kernel.org/stable/c/24376458138387fb251e782e624c7776e9826796patch
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.