CyberSecBulletin
CVE-2026-46124NVD status: Undergoing Analysis

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2026-46124 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions ee0024f5a7e3c73aa253869fae9650ae054093ca, 31dbb4ba0f719ae7774e4c0c95172c9bf81692f5, 908a76f0b1038035e6ebb4f2293ce079f92e0a02 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.48% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to ee0024f5a7e3c73aa253869fae9650ae054093ca or 31dbb4ba0f719ae7774e4c0c95172c9bf81692f5 or 908a76f0b1038035e6ebb4f2293ce079f92e0a02 or bb0988ed4f2e26d59bbb58f644cb3a55b7521e21, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.5 or 5.10.258 or 5.15.209 or 6.1.175, whichever matches your release line, or a later version.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux5e7de55602c61c8ff28db075cc49c8dd6989d7e0 up to, but not including, ee0024f5a7e3c73aa253869fae9650ae054093ca; 63d5a3e207bf315a32c7d16de6c89753a759f95a up to, but not including, 31dbb4ba0f719ae7774e4c0c95172c9bf81692f5; 0fdafdaef796816a9ed0fd7ac812932d569d9beb up to, but not including, 908a76f0b1038035e6ebb4f2293ce079f92e0a02; 952e7a7e317f126d0a2b879fc531b716932d5ffa up to, but not including, bb0988ed4f2e26d59bbb58f644cb3a55b7521e21; 56dfffea9fd3be0b3795a9ca6401e133a8427e0b up to, but not including, 0a1af74ae2177bda3aee0837a0546309aa539d0d; 0405d4b63d082861f4eaff9d39c78ee9dc34f845 up to, but not including, afbafeddf23db13fe2edb2d5c0bf4bbb13d7881b; 0405d4b63d082861f4eaff9d39c78ee9dc34f845 up to, but not including, 4c721a1d9b3c4fcaf59cc9b2281e3ec5a043e1a6; 0405d4b63d082861f4eaff9d39c78ee9dc34f845 up to, but not including, 24376458138387fb251e782e624c7776e9826796; and 10 more rangesee0024f5a7e3c73aa253869fae9650ae054093ca, 31dbb4ba0f719ae7774e4c0c95172c9bf81692f5, 908a76f0b1038035e6ebb4f2293ce079f92e0a02, bb0988ed4f2e26d59bbb58f644cb3a55b7521e21, 0a1af74ae2177bda3aee0837a0546309aa539d0d, afbafeddf23db13fe2edb2d5c0bf4bbb13d7881b
SiemensSIMATIC S7-1500 TM MFP - GNU/Linux subsystemall versionsNot stated
LinuxLinux Kernel5.4.293 up to, but not including, 5.5; 5.10.237 up to, but not including, 5.10.258; 5.15.181 up to, but not including, 5.15.209; 6.1.135 up to, but not including, 6.1.175; 6.6.88 up to, but not including, 6.6.140; 6.12.25 up to, but not including, 6.12.88; 6.14.4 up to, but not including, 6.15; 6.15.1 up to, but not including, 6.18.30; and 3 more ranges5.5, 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
NoneNothing can be modified.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by CNA.

Official 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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.

More Out-of-bounds Read vulnerabilities (CWE-125)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Read vulnerabilities

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