Tracker / CVE-2026-53402
CVE-2026-53402
In the Linux kernel, the following vulnerability has been resolved: fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font() When fbcon_do_set_font() fails (e.g., due to a memory allocation failure inside vc_resize() under heavy memory pressure), it jumps to the `err_out` label to roll back the console state. However, the current rollback logic forgets to restore the `hi_font` state, leading to a severe state machine corruption. Earlier in the function, `set_vc_hi_font()` might be called to change `vc->vc_hi_font_mask` and mutate the screen buffer. If `vc_resize()` subsequently fails, the `err_out` path restores `vc_font.charcount` but entirely skips rolling back the `vc_hi_font_mask` and the screen buffer. This mismatch leaves the terminal in a desynchronized state. Because `vc_hi_font_mask` remains set, the VT subsystem will still accept character indices greater than 255 from userspace and write them to the screen buffer. Subsequent rendering calls (e.g., `fbcon_putcs()`) will then use these inflated indices to access the reverted, 256-character font array, leading to a deterministic out-of-bounds read and potential kernel memory disclosure. Fix this by adding the missing rollback logic for the `hi_font` mask and screen buffer in the error path.
Affected products and versions
| linux | linux_kernel |
|---|---|
| linux | linux_kernel · 5.10.249 → 5.10.261 |
| linux | linux_kernel · 5.15.64 → 5.15.212 |
| linux | linux_kernel · 5.19.6 → 6.0 |
| linux | linux_kernel · 6.0.1 → 6.1.178 |
| linux | linux_kernel · 6.13 → 6.18.39 |
| linux | linux_kernel · 6.19 → 7.1.3 |
| linux | linux_kernel · 6.2 → 6.6.145 |
| linux | linux_kernel · 6.7 → 6.12.96 |