Vulnerability in Linux
CVE-2025-40304
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.
EPSS: 0.002 (7.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Linux — versions 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 2.6.12, 0
References
Frequently asked questions
- What is CVE-2025-40304?
- CVE-2025-40304 is a high-severity vulnerability in Linux. CVSS score: 7.8/10. Published 2025-12-08.
- How severe is CVE-2025-40304?
- High severity. CVSS v3 base score is 7.8 out of 10.