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CVE-2025-38685
fbdev: Fix vmalloc out-of-bounds write in fast_imageblit
Description

In the Linux kernel, the following vulnerability has been resolved: fbdev: Fix vmalloc out-of-bounds write in fast_imageblit This issue triggers when a userspace program does an ioctl FBIOPUT_CON2FBMAP by passing console number and frame buffer number. Ideally this maps console to frame buffer and updates the screen if console is visible. As part of mapping it has to do resize of console according to frame buffer info. if this resize fails and returns from vc_do_resize() and continues further. At this point console and new frame buffer are mapped and sets display vars. Despite failure still it continue to proceed updating the screen at later stages where vc_data is related to previous frame buffer and frame buffer info and display vars are mapped to new frame buffer and eventully leading to out-of-bounds write in fast_imageblit(). This bheviour is excepted only when fg_console is equal to requested console which is a visible console and updates screen with invalid struct references in fbcon_putcs().

INFO

Published Date :

Sept. 4, 2025, 4:15 p.m.

Last Modified :

Sept. 5, 2025, 5:47 p.m.

Remotely Exploit :

No

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products

The following products are affected by CVE-2025-38685 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
Solution
Apply the Linux kernel patch to fix the vmalloc out-of-bounds write in fast_imageblit.
  • Update the Linux kernel to the patched version.
  • Recompile the kernel if not using a pre-built package.
  • Reboot the system after updating the kernel.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2025-38685.

URL Resource
https://git.kernel.org/stable/c/078e62bffca4b7e72e8f3550eb063ab981c36c7a
https://git.kernel.org/stable/c/27b118aebdd84161c8ff5ce49d9d536f2af10754
https://git.kernel.org/stable/c/4c4d7ddaf1d43780b106bedc692679f965dc5a3a
https://git.kernel.org/stable/c/56701bf9eeb63219e378cb7fcbd066ea4eaeeb50
https://git.kernel.org/stable/c/af0db3c1f898144846d4c172531a199bb3ca375d
https://git.kernel.org/stable/c/cfec17721265e72e50cc69c6004fe3475cd38df2
https://git.kernel.org/stable/c/ed9b8e5016230868c8d813d9179523f729fec8c6
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2025-38685 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2025-38685 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2025-38685 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2025-38685 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Sep. 04, 2025

    Action Type Old Value New Value
    Added Description In the Linux kernel, the following vulnerability has been resolved: fbdev: Fix vmalloc out-of-bounds write in fast_imageblit This issue triggers when a userspace program does an ioctl FBIOPUT_CON2FBMAP by passing console number and frame buffer number. Ideally this maps console to frame buffer and updates the screen if console is visible. As part of mapping it has to do resize of console according to frame buffer info. if this resize fails and returns from vc_do_resize() and continues further. At this point console and new frame buffer are mapped and sets display vars. Despite failure still it continue to proceed updating the screen at later stages where vc_data is related to previous frame buffer and frame buffer info and display vars are mapped to new frame buffer and eventully leading to out-of-bounds write in fast_imageblit(). This bheviour is excepted only when fg_console is equal to requested console which is a visible console and updates screen with invalid struct references in fbcon_putcs().
    Added Reference https://git.kernel.org/stable/c/078e62bffca4b7e72e8f3550eb063ab981c36c7a
    Added Reference https://git.kernel.org/stable/c/27b118aebdd84161c8ff5ce49d9d536f2af10754
    Added Reference https://git.kernel.org/stable/c/4c4d7ddaf1d43780b106bedc692679f965dc5a3a
    Added Reference https://git.kernel.org/stable/c/56701bf9eeb63219e378cb7fcbd066ea4eaeeb50
    Added Reference https://git.kernel.org/stable/c/af0db3c1f898144846d4c172531a199bb3ca375d
    Added Reference https://git.kernel.org/stable/c/cfec17721265e72e50cc69c6004fe3475cd38df2
    Added Reference https://git.kernel.org/stable/c/ed9b8e5016230868c8d813d9179523f729fec8c6
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
No CVSS metrics available for this vulnerability.