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CVE-2026-46064NVD status: Undergoing Analysis

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2026-46064 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions ca1c857e2bb74a9fc0606128334f85316d57067b, b870f652877bfbe321bd0f4096fc37a93296f7b6, ce57fa439bd1b5d664f334a0c3e3f0e42abb0153 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 0.14% 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 ca1c857e2bb74a9fc0606128334f85316d57067b or b870f652877bfbe321bd0f4096fc37a93296f7b6 or ce57fa439bd1b5d664f334a0c3e3f0e42abb0153 or fd19eb1c75047a4ed4e855f56cafd704dc3914e0, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.258 or 5.15.209 or 6.1.175 or 6.6.140, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, ca1c857e2bb74a9fc0606128334f85316d57067b; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, b870f652877bfbe321bd0f4096fc37a93296f7b6; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, ce57fa439bd1b5d664f334a0c3e3f0e42abb0153; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, fd19eb1c75047a4ed4e855f56cafd704dc3914e0; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, fe31722b0194ff76bf8b461e8bf97a2081147787; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, c1c2417c60dbdca5ebb00462f21ee71c2d7f7083; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 9e8f6c9d4ecddda2f28baa1678340286cff3969c; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 9aad71144fa3682cca3837a06c8623016790e7ec; and 1 more rangesca1c857e2bb74a9fc0606128334f85316d57067b, b870f652877bfbe321bd0f4096fc37a93296f7b6, ce57fa439bd1b5d664f334a0c3e3f0e42abb0153, fd19eb1c75047a4ed4e855f56cafd704dc3914e0, fe31722b0194ff76bf8b461e8bf97a2081147787, c1c2417c60dbdca5ebb00462f21ee71c2d7f7083
SiemensSIMATIC S7-1500 TM MFP - GNU/Linux subsystemall versionsNot stated
LinuxLinux Kernel2.6.12.1 up to, but not including, 5.10.258; 5.11 up to, but not including, 5.15.209; 5.16 up to, but not including, 6.1.175; 6.2 up to, but not including, 6.6.140; 6.7 up to, but not including, 6.12.86; 6.13 up to, but not including, 6.18.27; 6.19 up to, but not including, 7.0.4; 2.6.125.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.86, 6.18.27

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
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
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
HighThe component can be taken down completely.

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

Official description

In the Linux kernel, the following vulnerability has been resolved: ibmasm: fix heap over-read in ibmasm_send_i2o_message() The ibmasm_send_i2o_message() function uses get_dot_command_size() to compute the byte count for memcpy_toio(), but this value is derived from user-controlled fields in the dot_command_header (command_size: u8, data_size: u16) and is never validated against the actual allocation size. A root user can write a small buffer with inflated header fields, causing memcpy_toio() to read up to ~65 KB past the end of the allocation into adjacent kernel heap, which is then forwarded to the service processor over MMIO. Silently clamping the copy size is not sufficient: if the header fields claim a larger size than the buffer, the SP receives a dot command whose own header is inconsistent with the I2O message length, which can cause the SP to desynchronize. Reject such commands outright by returning failure. Validate command_size before calling get_mfa_inbound() to avoid leaking an I2O message frame: reading INBOUND_QUEUE_PORT dequeues a hardware frame from the controller's free pool, and returning without a corresponding set_mfa_inbound() call would permanently exhaust it. Additionally, clamp command_size to I2O_COMMAND_SIZE before the memcpy_toio() so the MMIO write stays within the I2O message frame, consistent with the clamping already performed by outgoing_message_size() for the header field.

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. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Read vulnerabilities

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