CyberSecBulletin
CVE-2025-21772NVD status: Modified

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2025-21772 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 a3e77da9f843e4ab93917d30c314f0283e28c124, 213ba5bd81b7e97ac6e6190b8f3bc6ba76123625, 40a35d14f3c0dc72b689061ec72fc9b193f37d1f 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 0.24% 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 a3e77da9f843e4ab93917d30c314f0283e28c124 or 213ba5bd81b7e97ac6e6190b8f3bc6ba76123625 or 40a35d14f3c0dc72b689061ec72fc9b193f37d1f or 27a39d006f85e869be68c1d5d2ce05e5d6445bf5, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.4.291 or 5.10.235 or 5.15.179 or 6.1.129, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux02e2a5bfebe99edcf9d694575a75032d53fe1b73 up to, but not including, a3e77da9f843e4ab93917d30c314f0283e28c124; 02e2a5bfebe99edcf9d694575a75032d53fe1b73 up to, but not including, 213ba5bd81b7e97ac6e6190b8f3bc6ba76123625; 02e2a5bfebe99edcf9d694575a75032d53fe1b73 up to, but not including, 40a35d14f3c0dc72b689061ec72fc9b193f37d1f; 02e2a5bfebe99edcf9d694575a75032d53fe1b73 up to, but not including, 27a39d006f85e869be68c1d5d2ce05e5d6445bf5; 02e2a5bfebe99edcf9d694575a75032d53fe1b73 up to, but not including, 92527100be38ede924768f4277450dfe8a40e16b; 02e2a5bfebe99edcf9d694575a75032d53fe1b73 up to, but not including, 6578717ebca91678131d2b1f4ba4258e60536e9f; 02e2a5bfebe99edcf9d694575a75032d53fe1b73 up to, but not including, 7fa9706722882f634090bfc9af642bf9ed719e27; 02e2a5bfebe99edcf9d694575a75032d53fe1b73 up to, but not including, 80e648042e512d5a767da251d44132553fe04ae0; and 11 more rangesa3e77da9f843e4ab93917d30c314f0283e28c124, 213ba5bd81b7e97ac6e6190b8f3bc6ba76123625, 40a35d14f3c0dc72b689061ec72fc9b193f37d1f, 27a39d006f85e869be68c1d5d2ce05e5d6445bf5, 92527100be38ede924768f4277450dfe8a40e16b, 6578717ebca91678131d2b1f4ba4258e60536e9f
SiemensSIMATIC S7-1500 TM MFP - GNU/Linux subsystemall versionsNot stated
LinuxLinux Kernelbefore 5.4.291; 5.5 up to, but not including, 5.10.235; 5.11 up to, but not including, 5.15.179; 5.16 up to, but not including, 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; 6.145.4.291, 5.10.235, 5.15.179, 6.1.129, 6.6.79, 6.12.16

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: partitions: mac: fix handling of bogus partition table Fix several issues in partition probing: - The bailout for a bad partoffset must use put_dev_sector(), since the preceding read_part_sector() succeeded. - If the partition table claims a silly sector size like 0xfff bytes (which results in partition table entries straddling sector boundaries), bail out instead of accessing out-of-bounds memory. - We must not assume that the partition table contains proper NUL termination - use strnlen() and strncmp() instead of strlen() and strcmp().

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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