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 :
Jan. 8, 2026, 10:31 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] |
Solution
- 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.
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.
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.
-
Initial Analysis by [email protected]
Jan. 08, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-787 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:2.6.12:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:2.6.12:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:2.6.12:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:2.6.12:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:2.6.12:-:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.103 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.43 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.15.11 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.16 up to (excluding) 6.16.2 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 6.1.149 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 2.6.13 up to (excluding) 5.15.190 Added CPE Configuration OR *cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* Added Reference Type kernel.org: https://git.kernel.org/stable/c/078e62bffca4b7e72e8f3550eb063ab981c36c7a Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/27b118aebdd84161c8ff5ce49d9d536f2af10754 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/4c4d7ddaf1d43780b106bedc692679f965dc5a3a Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/56701bf9eeb63219e378cb7fcbd066ea4eaeeb50 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/af0db3c1f898144846d4c172531a199bb3ca375d Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/cfec17721265e72e50cc69c6004fe3475cd38df2 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/ed9b8e5016230868c8d813d9179523f729fec8c6 Types: Patch Added Reference Type CVE: https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html Types: Third Party Advisory -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 03, 2025
Action Type Old Value New Value Added Reference https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html -
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