CyberSecBulletin
CVE-2025-38702NVD status: Modified

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2025-38702 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 5c3f5a25c62230b7965804ce7a2e9305c3ca3961, cbe740de32bb0fb7a5213731ff5f26ea6718fca3, 806f85bdd3a60187c21437fc51baace11f659f35 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 0.2% 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 5c3f5a25c62230b7965804ce7a2e9305c3ca3961 or cbe740de32bb0fb7a5213731ff5f26ea6718fca3 or 806f85bdd3a60187c21437fc51baace11f659f35 or 2828a433c7d7a05b6f27c8148502095101dd0b09, whichever matches your release line, or a later version.
  2. Update SIMATIC CN 4100 to V5.0 or a later version.
  3. Update Linux Kernel to 6.1.149 or 6.6.103 or 6.12.43 or 6.15.11, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 5c3f5a25c62230b7965804ce7a2e9305c3ca3961; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, cbe740de32bb0fb7a5213731ff5f26ea6718fca3; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 806f85bdd3a60187c21437fc51baace11f659f35; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 2828a433c7d7a05b6f27c8148502095101dd0b09; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 248b2aab9b2af5ecf89d9d7955a2ff20c4b4a399; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 523b84dc7ccea9c4d79126d6ed1cf9033cf83b05; 2.6.125c3f5a25c62230b7965804ce7a2e9305c3ca3961, cbe740de32bb0fb7a5213731ff5f26ea6718fca3, 806f85bdd3a60187c21437fc51baace11f659f35, 2828a433c7d7a05b6f27c8148502095101dd0b09, 248b2aab9b2af5ecf89d9d7955a2ff20c4b4a399, 523b84dc7ccea9c4d79126d6ed1cf9033cf83b05
SiemensSIMATIC CN 4100before V5.0V5.0
SiemensSIMATIC S7-1500 CPU 1518-4 PN/DP MFPV3.1.5 and laterNot stated
SiemensSIMATIC S7-1500 CPU 1518F-4 PN/DP MFPV3.1.5 and laterNot stated
SiemensSIPLUS S7-1500 CPU 1518-4 PN/DP MFPV3.1.5 and laterNot stated
LinuxLinux Kernel2.6.12.1 up to, but not including, 6.1.149; 6.2 up to, but not including, 6.6.103; 6.7 up to, but not including, 6.12.43; 6.13 up to, but not including, 6.15.11; 6.16 up to, but not including, 6.16.2; 2.6.126.1.149, 6.6.103, 6.12.43, 6.15.11, 6.16.2
DebianDebian Linux11.0Not stated

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: fbdev: fix potential buffer overflow in do_register_framebuffer() The current implementation may lead to buffer overflow when: 1. Unregistration creates NULL gaps in registered_fb[] 2. All array slots become occupied despite num_registered_fb < FB_MAX 3. The registration loop exceeds array bounds Add boundary check to prevent registered_fb[FB_MAX] access.

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

Third-party and government advisories

Recent Out-of-bounds Write vulnerabilities

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