CyberSecBulletin
CVE-2025-21780NVD status: Modified

Linux: Buffer Copy without Checking Size of Input

Published Updated By the CyberSecBulletin desk

CVE-2025-21780 is a high-severity buffer copy without checking size of input 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 3484ea33157bc7334f57e64826ec5a4bf992151a, e43a8b9c4d700ffec819c5043a48769b3e7d9cab, 2498d2db1d35e88a2060ea191ae75dce853dd084 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 0.26% 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 3484ea33157bc7334f57e64826ec5a4bf992151a or e43a8b9c4d700ffec819c5043a48769b3e7d9cab or 2498d2db1d35e88a2060ea191ae75dce853dd084 or 231075c5a8ea54f34b7c4794687baa980814e6de, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.1.129 or 6.6.79 or 6.12.16 or 6.13.4, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux137d63abbf6a0859e79b662e81d21170ecb75e59 up to, but not including, 3484ea33157bc7334f57e64826ec5a4bf992151a; 137d63abbf6a0859e79b662e81d21170ecb75e59 up to, but not including, e43a8b9c4d700ffec819c5043a48769b3e7d9cab; 137d63abbf6a0859e79b662e81d21170ecb75e59 up to, but not including, 2498d2db1d35e88a2060ea191ae75dce853dd084; 137d63abbf6a0859e79b662e81d21170ecb75e59 up to, but not including, 231075c5a8ea54f34b7c4794687baa980814e6de; 137d63abbf6a0859e79b662e81d21170ecb75e59 up to, but not including, 1abb2648698bf10783d2236a6b4a7ca5e8021699; 5.23484ea33157bc7334f57e64826ec5a4bf992151a, e43a8b9c4d700ffec819c5043a48769b3e7d9cab, 2498d2db1d35e88a2060ea191ae75dce853dd084, 231075c5a8ea54f34b7c4794687baa980814e6de, 1abb2648698bf10783d2236a6b4a7ca5e8021699
SiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)V3.1.6 and later; V3.1.7 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0)V3.1.6 and later; V3.1.7 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0)V3.1.6 and later; V3.1.7 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0)V3.1.6 and later; V3.1.7 and laterNot stated
SiemensSIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0)V3.1.6 and later; V3.1.7 and laterNot stated
LinuxLinux Kernelbefore 6.1.129; 6.2 up to, but not including, 6.6.79; 6.7 up to, but not including, 6.12.16; 6.13 up to, but not including, 6.13.4; 6.146.1.129, 6.6.79, 6.12.16, 6.13.4

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
CVSS 3.17.8HighCISA (ADP)

Official description

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: avoid buffer overflow attach in smu_sys_set_pp_table() It malicious user provides a small pptable through sysfs and then a bigger pptable, it may cause buffer overflow attack in function smu_sys_set_pp_table().

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

The underlying weakness: Buffer Copy without Checking Size of Input

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output 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 Buffer Copy without Checking Size of Input vulnerabilities (CWE-120)

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 Buffer Copy without Checking Size of Input vulnerabilities

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