CVE-2025-40304

High

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.

SeverityHigh
CVSS7.8
Exploit probability—
ProductLinux
PublishedDec 8, 2025
First seenDec 8, 2025

How to fix

Update
  • Linux Linux996bfaa7372d6718b6d860bdf78f6618e850c702, f0982400648a3e00580253e0c48e991f34d2684c, 1943b69e87b0ab35032d47de0a7fca9a3d1d6fc1, ebc0730b490c7f27340b1222e01dd106e820320d, 86df8ade88d290725554cefd03101ecd0fbd3752, 15ba9acafb0517f8359ca30002c189a68ddbb939, 2d1359e11674ed4274934eac8a71877ae5ae7bbb, 3637d34b35b287ab830e66048841ace404382b67 or later

Affected products

ProductAffected versionsFixed in
Linux Linux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 ≤ v < 996bfaa7372d6718b6d860bdf78f6618e850c702, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 ≤ v < f0982400648a3e00580253e0c48e991f34d2684c, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 ≤ v < 1943b69e87b0ab35032d47de0a7fca9a3d1d6fc1, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 ≤ v < ebc0730b490c7f27340b1222e01dd106e820320d, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 ≤ v < 86df8ade88d290725554cefd03101ecd0fbd3752, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 ≤ v < 15ba9acafb0517f8359ca30002c189a68ddbb939, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 ≤ v < 2d1359e11674ed4274934eac8a71877ae5ae7bbb, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 ≤ v < 3637d34b35b287ab830e66048841ace404382b67, 2.6.12996bfaa7372d6718b6d860bdf78f6618e850c702, f0982400648a3e00580253e0c48e991f34d2684c, 1943b69e87b0ab35032d47de0a7fca9a3d1d6fc1, ebc0730b490c7f27340b1222e01dd106e820320d, 86df8ade88d290725554cefd03101ecd0fbd3752, 15ba9acafb0517f8359ca30002c189a68ddbb939, 2d1359e11674ed4274934eac8a71877ae5ae7bbb, 3637d34b35b287ab830e66048841ace404382b67

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.

CVE-2025-40304 · Linux · Dark Radar