{"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":"high","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"},{"url":"https://git.kernel.org/stable/c/cb016bcb40c81e7b19c4ae6143babb366dae8e20"},{"url":"https://git.kernel.org/stable/c/ac562193c36696513ae196171892e9338475c4bc"},{"url":"https://git.kernel.org/stable/c/3618a4c5b2591cfa83efe74f5b18c2d02b35c3f5"},{"url":"https://git.kernel.org/stable/c/a7a526fbc847f07ad3a503c7382189be5ab68574"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-07-19T23:34:10.558Z","epss":0.00171,"epssPercentile":0.06477,"vendor":"Linux","product":"Linux","affected":["Linux >= 868749a7456dc48e93887a8474194e2ee6d6c21f < cb016bcb40c81e7b19c4ae6143babb366dae8e20","Linux >= ebd6f886aa2447fcfcdce5450c9e1028e1d681bb < ac562193c36696513ae196171892e9338475c4bc","Linux >= a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 < 3618a4c5b2591cfa83efe74f5b18c2d02b35c3f5","Linux >= a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 < a7a526fbc847f07ad3a503c7382189be5ab68574","Linux >= a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 < b5bb2c696e140c399cb874def2feedf61dee27d6","Linux >= a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 < 076b1aa65f77a49bce5a48a4a55a397cfcafa2b8","Linux >= a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 < 39815715cbcfabb16fc8c5f4a23deeda20f5df62","Linux >= a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 < 8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2","Linux f08ccb792d3eaf1dc62d8cbf6a30d6522329f660","Linux >= 5.10.249 < 5.10.261","Linux >= 5.15.64 < 5.15.212","Linux >= 5.19.6 < 5.20","Linux 6.0"],"cvss":7.1,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-16T15:30:33.058892Z"},"cvssSource":"cna","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":"twilight","depthScore":39,"depthScoreParts":{"impact":39.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":223130,"id":"CVE-2026-53402","ts":1792172307605,"field":"cvss","old":null,"new":"7.1"},{"seq":223129,"id":"CVE-2026-53402","ts":1792172307605,"field":"severity","old":"none","new":"high"}]}