CVE-2022-50221 Information

Jun 19, 2025 cve

Description

In the Linux kernel the following vulnerability has been resolved:

drm/fb-helper: Fix out-of-bounds access

Clip memory range to screen-buffer size to avoid out-of-bounds access in fbdev deferred I/O’s damage handling.

Fbdev’s deferred I/O can only track pages. From the range of pages the damage handler computes the clipping rectangle for the display update. If the fbdev screen buffer ends near the beginning of a page that page could contain more scanlines. The damage handler would then track these non-existing scanlines as dirty and provoke an out-of-bounds access during the screen update. Hence clip the maximum memory range to the size of the screen buffer.

While at it rename the variables min/max to min_off/max_off in drm_fb_helper_deferred_io(). This avoids confusion with the macros of the same name.

Reference

https://git.kernel.org/stable/c/9c49ac792c639dbec0728b513329a32461f72253 https://git.kernel.org/stable/c/ae25885bdf59fde40726863c57fd20e4a0642183

CNNVD-202506-2511 (Published: 2025-06-18)

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