Out-of-Bounds Write Vulnerability in Linux Kernel Graphics Rendering

CVE-2025-40304

What is CVE-2025-40304?

The Linux kernel has addressed a significant vulnerability affecting framebuffer handling, specifically in the bit_putcs function. This issue allowed for potential out-of-bounds writes when rendering text near the edges of the screen. Implementing bounds checking ensures that writes do not extend beyond framebuffer limits. The updated mechanism stops the rendering process if the Y position exceeds screen boundaries and adjusts the image height accordingly to prevent mismatched buffer sizes. This fix also ensures that the character count aligns with the clipped width of the image, mitigating the risk of buffer overflows that could compromise system stability and security.

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