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Permalink CVE-2026-53402
7.1 HIGH
  • CVSS version (CVSS): 3.1
  • Attack Vector (AV): Local (L)
  • Attack Complexity (AC): Low (L)
  • Privileges Required (PR): Low (L)
  • User Interaction (UI): None (N)
  • Scope (S): Unchanged (U)
  • Confidentiality (C): High (H)
  • Integrity (I): None (N)
  • Availability (A): High (H)
  • Modified Attack Vector (MAV): Local (L)
  • Modified Attack Complexity (MAC): Low (L)
  • Modified Privileges Required (MPR): Low (L)
  • Modified User Interaction (MUI): None (N)
  • Modified Confidentiality (MC): High (H)
  • Modified Scope (MS): Unchanged (U)
  • Modified Integrity (MI): None (N)
  • Modified Availability (MA): High (H)
created 6 days, 6 hours ago Activity log
  • Created & dismissed (max. allowed matches exceeded) suggestion
fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()

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

Linux
  • <076b1aa65f77a49bce5a48a4a55a397cfcafa2b8
  • ==f08ccb792d3eaf1dc62d8cbf6a30d6522329f660
  • <5.16
  • ==ebd6f886aa2447fcfcdce5450c9e1028e1d681bb
  • <6.0
  • <39815715cbcfabb16fc8c5f4a23deeda20f5df62
  • =<6.18.*
  • <5.11
  • <8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2
  • =<6.12.*
  • =<7.1.*
  • ==6.0
  • <5.20
  • =<*
  • ==868749a7456dc48e93887a8474194e2ee6d6c21f
  • <b5bb2c696e140c399cb874def2feedf61dee27d6