{"id":"CVE-2026-53402","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()\n\nWhen fbcon_do_set_font() fails (e.g., due to a memory allocation failure\ninside vc_resize() unde…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()\n\nWhen fbcon_do_set_font() fails (e.g., due to a memory allocation failure\ninside vc_resize() unde…","severity":"none","published":"2026-07-19","updated":"2026-07-19","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-53402","references":[{"url":"https://git.kernel.org/stable/c/076b1aa65f77a49bce5a48a4a55a397cfcafa2b8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/39815715cbcfabb16fc8c5f4a23deeda20f5df62","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b5bb2c696e140c399cb874def2feedf61dee27d6","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"ingestedAt":"2026-07-19T23:34:10.558Z","epss":0.00135,"epssPercentile":0.03362,"slug":"CVE-2026-53402","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()\n\nWhen fbcon_do_set_font() fails (e.g., due to a memory allocation failure\ninside vc_resize() under heavy memory pressure), it jumps to the `err_out`\nlabel to roll back the console state. However, the current rollback logic\nforgets to restore the `hi_font` state, leading to a severe state machine\ncorruption.\n\nEarlier in the function, `set_vc_hi_font()` might be called to change\n`vc->vc_hi_font_mask` and mutate the screen buffer. If `vc_resize()`\nsubsequently fails, the `err_out` path restores `vc_font.charcount`\nbut entirely skips rolling back the `vc_hi_font_mask` and the screen\nbuffer.\n\nThis mismatch leaves the terminal in a desynchronized state. Because\n`vc_hi_font_mask` remains set, the VT subsystem will still accept\ncharacter indices greater than 255 from userspace and write them to the\nscreen buffer. Subsequent rendering calls (e.g., `fbcon_putcs()`) will\nthen use these inflated indices to access the reverted, 256-character\nfont array, leading to a deterministic out-of-bounds read and potential\nkernel memory disclosure.\n\nFix this by adding the missing rollback logic for the `hi_font` mask\nand screen buffer in the error path.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}