CyberSecBulletin
CVE-2026-64085NVD status: Analyzed

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2026-64085 is a high-severity out-of-bounds write vulnerability in Linux, with a CVSS 3.1 base score of 7.8 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 7896d87cbb05e097efc113243d4e38f9f8cea16c, 9d5309500b4607b7198e19f0a3fa13eb864cd5fb, 6098634cfa711f11a8d65368dc51ec8f7c8241ba 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 7896d87cbb05e097efc113243d4e38f9f8cea16c or 9d5309500b4607b7198e19f0a3fa13eb864cd5fb or 6098634cfa711f11a8d65368dc51ec8f7c8241ba or 60c4b9fe1a3dd012014b1f561a6928a0b5db1126, 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 6.6.142, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux407dc802a9c0809ca6a48de4b4c63305eb84ef56 up to, but not including, 7896d87cbb05e097efc113243d4e38f9f8cea16c; 407dc802a9c0809ca6a48de4b4c63305eb84ef56 up to, but not including, 9d5309500b4607b7198e19f0a3fa13eb864cd5fb; 407dc802a9c0809ca6a48de4b4c63305eb84ef56 up to, but not including, 6098634cfa711f11a8d65368dc51ec8f7c8241ba; 407dc802a9c0809ca6a48de4b4c63305eb84ef56 up to, but not including, 60c4b9fe1a3dd012014b1f561a6928a0b5db1126; 407dc802a9c0809ca6a48de4b4c63305eb84ef56 up to, but not including, 83e039f0a43e0708515b0479cb7690fb93faaaa0; 407dc802a9c0809ca6a48de4b4c63305eb84ef56 up to, but not including, 97a9cf2a8217ca1cdaf48cb9ab26e471632c7e7f; 407dc802a9c0809ca6a48de4b4c63305eb84ef56 up to, but not including, dd47b8c4a0a8ced442da3f008db28fbbd31feaf0; 407dc802a9c0809ca6a48de4b4c63305eb84ef56 up to, but not including, 43cae21424ff8e33894a0f86c6b80b840c049fd7; and 1 more ranges7896d87cbb05e097efc113243d4e38f9f8cea16c, 9d5309500b4607b7198e19f0a3fa13eb864cd5fb, 6098634cfa711f11a8d65368dc51ec8f7c8241ba, 60c4b9fe1a3dd012014b1f561a6928a0b5db1126, 83e039f0a43e0708515b0479cb7690fb93faaaa0, 97a9cf2a8217ca1cdaf48cb9ab26e471632c7e7f
LinuxLinux Kernel5.10 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, 6.6.142; 6.7 up to, but not including, 6.12.92; 6.13 up to, but not including, 6.18.34; 6.19 up to, but not including, 7.0.11; 7.15.10.258, 5.15.209, 6.1.175, 6.6.142, 6.12.92, 6.18.34

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
HighData or code can be modified at will.
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:H/A:H. Scored by NVD.

Official description

In the Linux kernel, the following vulnerability has been resolved: hwmon: (pmbus/adm1266) bounce blackbox records through a protocol-sized buffer adm1266_pmbus_block_xfer() copies the device-supplied block payload into the caller-provided buffer using the device-supplied length: memcpy(data_r, &msgs[1].buf[1], msgs[1].buf[0]); The helper does not know how large data_r is and trusts the device to return at most one record's worth of bytes. adm1266_nvmem_read_blackbox() violates that contract: it advances read_buff inside data->dev_mem in ADM1266_BLACKBOX_SIZE (64-byte) strides while the helper is willing to write up to ADM1266_PMBUS_BLOCK_MAX (255) bytes. A device that returns more than 64 bytes on the trailing record (read_buff offset 1984 in the 2048-byte dev_mem allocation) overflows dev_mem by up to 191 bytes before the post-call if (ret != ADM1266_BLACKBOX_SIZE) return -EIO; can reject the response. Contain the fix in the caller without changing the helper signature: read each record into a 255-byte local bounce buffer that matches the helper's maximum output, validate the returned length, and only then copy exactly ADM1266_BLACKBOX_SIZE bytes into the dev_mem slot.

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

The underlying weakness: Out-of-bounds Write

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

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Out-of-bounds Write vulnerabilities (CWE-787)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Write vulnerabilities

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