{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53402","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-06-09T07:44:35.403Z","datePublished":"2026-07-19T12:02:01.795Z","dateUpdated":"2026-08-17T04:50:55.659Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-17T04:50:55.659Z"},"descriptions":[{"lang":"en","value":"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() 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."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","baseScore":7.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerability is reached only through the KDFONTOP ioctl on a framebuffer-console virtual terminal (/dev/ttyN), which is a local syscall path with no network or physical-access vector.\nAC:L - An attacker who controls a session on an fbcon-backed VT can reliably trigger the bug by issuing a font-change ioctl with different dimensions and a 256↔512 glyph transition, then inducing vc_resize() failure through self-controlled memory pressure; no race or victim-dependent timing is required.\nPR:L - KDFONTOP font-set operations require only that the caller owns the controlling TTY (current->signal->tty == tty), which any unprivileged local user with a console or VT session has; CAP_SYS_TTY_CONFIG is not required on that path.\nUI:N - Exploitation requires only the attacker's own ioctl and memory-pressure actions on their TTY; no action by another user or administrator is needed.\nS:U - Impact is confined to kernel memory disclosure and potential kernel crash within the same kernel security authority; there is no VM escape, sandbox escape, or cross-security-boundary effect.\nC:H - The desynchronized hi_font_mask causes deterministic out-of-bounds reads from the kernel font glyph buffer during fbcon rendering (e.g., bit_cursor and rotated putcs paths), enabling disclosure of adjacent kernel memory.\nI:N - The flaw is an out-of-bounds read with console state desynchronization; it does not provide an arbitrary kernel write, code execution, or other data-modification primitive.\nA:H - Out-of-bounds reads from kernel font data can cause kernel page faults and oopses, consistent with the prior syzkaller-reported fbcon font/resize failure class that produced unhandled page faults."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/video/fbdev/core/fbcon.c"],"versions":[{"version":"868749a7456dc48e93887a8474194e2ee6d6c21f","lessThan":"cb016bcb40c81e7b19c4ae6143babb366dae8e20","status":"affected","versionType":"git"},{"version":"ebd6f886aa2447fcfcdce5450c9e1028e1d681bb","lessThan":"ac562193c36696513ae196171892e9338475c4bc","status":"affected","versionType":"git"},{"version":"a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24","lessThan":"3618a4c5b2591cfa83efe74f5b18c2d02b35c3f5","status":"affected","versionType":"git"},{"version":"a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24","lessThan":"a7a526fbc847f07ad3a503c7382189be5ab68574","status":"affected","versionType":"git"},{"version":"a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24","lessThan":"b5bb2c696e140c399cb874def2feedf61dee27d6","status":"affected","versionType":"git"},{"version":"a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24","lessThan":"076b1aa65f77a49bce5a48a4a55a397cfcafa2b8","status":"affected","versionType":"git"},{"version":"a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24","lessThan":"39815715cbcfabb16fc8c5f4a23deeda20f5df62","status":"affected","versionType":"git"},{"version":"a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24","lessThan":"8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2","status":"affected","versionType":"git"},{"version":"f08ccb792d3eaf1dc62d8cbf6a30d6522329f660","status":"affected","versionType":"git"},{"version":"5.10.249","lessThan":"5.10.261","status":"affected","versionType":"semver"},{"version":"5.15.64","lessThan":"5.15.212","status":"affected","versionType":"semver"},{"version":"5.19.6","lessThan":"5.20","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/video/fbdev/core/fbcon.c"],"versions":[{"version":"6.0","status":"affected"},{"version":"0","lessThan":"6.0","status":"unaffected","versionType":"semver"},{"version":"5.10.261","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.212","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.178","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.145","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.96","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.39","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.3","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.249","versionEndExcluding":"5.10.261"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.64","versionEndExcluding":"5.15.212"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0","versionEndExcluding":"6.1.178"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0","versionEndExcluding":"6.12.96"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0","versionEndExcluding":"6.18.39"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0","versionEndExcluding":"7.1.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0","versionEndExcluding":"7.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19.6"}]}]}],"references":[{"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"},{"url":"https://git.kernel.org/stable/c/b5bb2c696e140c399cb874def2feedf61dee27d6"},{"url":"https://git.kernel.org/stable/c/076b1aa65f77a49bce5a48a4a55a397cfcafa2b8"},{"url":"https://git.kernel.org/stable/c/39815715cbcfabb16fc8c5f4a23deeda20f5df62"},{"url":"https://git.kernel.org/stable/c/8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2"}],"title":"fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()","x_generator":{"engine":"bippy-1.2.0"}}}}