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CVE-2025-38568NVD status: Modified

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2025-38568 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 39491e859fd494d0b51adc5c7d54c8a7dcf1d198, d00e4125680f7074c4f42ce3c297336f23128e70, 66fc2ebdd9d5dd6e5a9c7edeace5a61a0ab2cd86 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 0.19% 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 39491e859fd494d0b51adc5c7d54c8a7dcf1d198 or d00e4125680f7074c4f42ce3c297336f23128e70 or 66fc2ebdd9d5dd6e5a9c7edeace5a61a0ab2cd86 or f1a9dbcb7d17bf0abb325cdc984957cfabc59693, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.6.102 or 6.12.42 or 6.15.10 or 6.16.1, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxf62af20bed2d9e824f51cfc97ff01bc261f40e58 up to, but not including, 39491e859fd494d0b51adc5c7d54c8a7dcf1d198; f62af20bed2d9e824f51cfc97ff01bc261f40e58 up to, but not including, d00e4125680f7074c4f42ce3c297336f23128e70; f62af20bed2d9e824f51cfc97ff01bc261f40e58 up to, but not including, 66fc2ebdd9d5dd6e5a9c7edeace5a61a0ab2cd86; f62af20bed2d9e824f51cfc97ff01bc261f40e58 up to, but not including, f1a9dbcb7d17bf0abb325cdc984957cfabc59693; f62af20bed2d9e824f51cfc97ff01bc261f40e58 up to, but not including, ffd2dc4c6c49ff4f1e5d34e454a6a55608104c17; 6.439491e859fd494d0b51adc5c7d54c8a7dcf1d198, d00e4125680f7074c4f42ce3c297336f23128e70, 66fc2ebdd9d5dd6e5a9c7edeace5a61a0ab2cd86, f1a9dbcb7d17bf0abb325cdc984957cfabc59693, ffd2dc4c6c49ff4f1e5d34e454a6a55608104c17
LinuxLinux Kernel6.4 up to, but not including, 6.6.102; 6.7 up to, but not including, 6.12.42; 6.13 up to, but not including, 6.15.10; 6.16 up to, but not including, 6.16.16.6.102, 6.12.42, 6.15.10, 6.16.1

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.

Scoring systemScoreSeverityScored by
CVSS 3.17.8HighCNA
CVSS 3.17.8HighNVD

Official description

In the Linux kernel, the following vulnerability has been resolved: net/sched: mqprio: fix stack out-of-bounds write in tc entry parsing TCA_MQPRIO_TC_ENTRY_INDEX is validated using NLA_POLICY_MAX(NLA_U32, TC_QOPT_MAX_QUEUE), which allows the value TC_QOPT_MAX_QUEUE (16). This leads to a 4-byte out-of-bounds stack write in the fp[] array, which only has room for 16 elements (0–15). Fix this by changing the policy to allow only up to TC_QOPT_MAX_QUEUE - 1.

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. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Write vulnerabilities

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