CVE-2025-40304

Linux Kernel - Out-of-Bounds Write in fbdev bit_putcs

Title source: llm
STIX 2.1

Description

In the Linux kernel, the following vulnerability has been resolved: fbdev: Add bounds checking in bit_putcs to fix vmalloc-out-of-bounds Add bounds checking to prevent writes past framebuffer boundaries when rendering text near screen edges. Return early if the Y position is off-screen and clip image height to screen boundary. Break from the rendering loop if the X position is off-screen. When clipping image width to fit the screen, update the character count to match the clipped width to prevent buffer size mismatches. Without the character count update, bit_putcs_aligned and bit_putcs_unaligned receive mismatched parameters where the buffer is allocated for the clipped width but cnt reflects the original larger count, causing out-of-bounds writes.

Scores

EPSS 0.0006
EPSS Percentile 17.9%

Details

Status published
Products (25)
linux/Kernel 2.6.12 - 5.4.302linux
linux/Kernel 5.11.0 - 5.15.197linux
linux/Kernel 5.16.0 - 6.1.159linux
linux/Kernel 5.5.0 - 5.10.247linux
linux/Kernel 6.13.0 - 6.17.8linux
linux/Kernel 6.2.0 - 6.6.117linux
linux/Kernel 6.7.0 - 6.12.58linux
Linux/Linux < 2.6.12
Linux/Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 - 15ba9acafb0517f8359ca30002c189a68ddbb939
Linux/Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 - 1943b69e87b0ab35032d47de0a7fca9a3d1d6fc1
... and 15 more
Published Dec 08, 2025
Tracked Since Feb 18, 2026