CyberSecBulletin
CVE-2025-38538NVD status: Analyzed

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2025-38538 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 84fff8e6f11b9af1407e273995b5257d99ff0cff, aec396b4f736f3f8d2c28a9cd2924a4ada57ae87, 24861ef8b517a309a4225f2793be0cd8fa0bec9e 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 84fff8e6f11b9af1407e273995b5257d99ff0cff or aec396b4f736f3f8d2c28a9cd2924a4ada57ae87 or 24861ef8b517a309a4225f2793be0cd8fa0bec9e or f366b36c5e3ce29c9a3c8eed3d1631908e4fc8bb, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.4.297 or 5.10.241 or 5.15.190 or 6.1.147, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxb45b262cefd5b8eb2ba88d20e5bd295881293894 up to, but not including, 84fff8e6f11b9af1407e273995b5257d99ff0cff; b45b262cefd5b8eb2ba88d20e5bd295881293894 up to, but not including, aec396b4f736f3f8d2c28a9cd2924a4ada57ae87; b45b262cefd5b8eb2ba88d20e5bd295881293894 up to, but not including, 24861ef8b517a309a4225f2793be0cd8fa0bec9e; b45b262cefd5b8eb2ba88d20e5bd295881293894 up to, but not including, f366b36c5e3ce29c9a3c8eed3d1631908e4fc8bb; b45b262cefd5b8eb2ba88d20e5bd295881293894 up to, but not including, 4bb016438335ec02b01f96bf1367378c2bfe03e5; b45b262cefd5b8eb2ba88d20e5bd295881293894 up to, but not including, 122160289adf8ebf15060f1cbf6265b55a914948; b45b262cefd5b8eb2ba88d20e5bd295881293894 up to, but not including, d6bbd67ab5de37a74ac85c83c5a26664b62034dd; b45b262cefd5b8eb2ba88d20e5bd295881293894 up to, but not including, 188c6ba1dd925849c5d94885c8bbdeb0b3dcf510; and 1 more ranges84fff8e6f11b9af1407e273995b5257d99ff0cff, aec396b4f736f3f8d2c28a9cd2924a4ada57ae87, 24861ef8b517a309a4225f2793be0cd8fa0bec9e, f366b36c5e3ce29c9a3c8eed3d1631908e4fc8bb, 4bb016438335ec02b01f96bf1367378c2bfe03e5, 122160289adf8ebf15060f1cbf6265b55a914948
LinuxLinux Kernel3.17 up to, but not including, 5.4.297; 5.5 up to, but not including, 5.10.241; 5.11 up to, but not including, 5.15.190; 5.16 up to, but not including, 6.1.147; 6.2 up to, but not including, 6.6.100; 6.7 up to, but not including, 6.12.40; 6.13 up to, but not including, 6.15.8; 6.165.4.297, 5.10.241, 5.15.190, 6.1.147, 6.6.100, 6.12.40
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: dmaengine: nbpfaxi: Fix memory corruption in probe() The nbpf->chan[] array is allocated earlier in the nbpf_probe() function and it has "num_channels" elements. These three loops iterate one element farther than they should and corrupt memory. The changes to the second loop are more involved. In this case, we're copying data from the irqbuf[] array into the nbpf->chan[] array. If the data in irqbuf[i] is the error IRQ then we skip it, so the iterators are not in sync. I added a check to ensure that we don't go beyond the end of the irqbuf[] array. I'm pretty sure this can't happen, but it seemed harmless to add a check. On the other hand, after the loop has ended there is a check to ensure that the "chan" iterator is where we expect it to be. In the original code we went one element beyond the end of the array so the iterator wasn't in the correct place and it would always return -EINVAL. However, now it will always be in the correct place. I deleted the check since we know the result.

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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