{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-40322","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T07:20:57.186Z","datePublished":"2025-12-08T00:46:49.773Z","dateUpdated":"2026-08-05T12:09:35.122Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:09:35.122Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: bitblit: bound-check glyph index in bit_putcs*\n\nbit_putcs_aligned()/unaligned() derived the glyph pointer from the\ncharacter value masked by 0xff/0x1ff, which may exceed the actual font's\nglyph count and read past the end of the built-in font array.\nClamp the index to the actual glyph count before computing the address.\n\nThis fixes a global out-of-bounds read reported by syzbot."}],"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 vulnerable render path is reached only through local interfaces — `KDFONTOP` ioctl on a VT plus writes to `/dev/vcsa*` or the tty itself. There is no remote or adjacent-network exposure of fbcon.\nAC:L - The attacker fully controls both the desync (choosing font dimensions that make `vc_do_resize()` fail deterministically via `new_screen_size > KMALLOC_MAX_SIZE` or `!new_screen_size`) and the trigger (writing glyph indices 256–511 into the screen buffer); syzbot has a working C reproducer.\nPR:L - `KDFONTOP(KD_FONT_OP_SET)` and `PIO_UNIMAP` only require `perm`, which is granted to any unprivileged user whose controlling tty is the VT (`current->signal->tty == tty`) — no capability is needed, and `vcs_open()` performs no capability check at all.\nUI:N - The attacker performs the font ioctl and the console write entirely from its own process; no victim action or cooperation is needed.\nS:U - The out-of-bounds read stays within the kernel's own memory and the impact is confined to the kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Up to 256 glyph cells are read past the font array — 4 KB beyond the global `fontdata_8x16`, or up to ~256 KB beyond a large user-supplied font — and those raw kernel bytes are blitted to the framebuffer as bitmaps that the attacker can read back via `/dev/fb0`, yielding a substantial kernel memory disclosure primitive.\nI:N - The defect is strictly an out-of-bounds read; the fetched bytes are copied into correctly sized pixmap and attribute buffers, so no kernel memory is modified and no write or control-flow primitive is produced.\nA:H - When the active font is a large kvmalloc-backed user font, the overrun can run hundreds of kilobytes past the allocation into a vmalloc guard page, faulting inside `bit_putcs()` while `console_lock` is held and oopsing/hanging the system; on KASAN builds it trips a report that can panic."}]}],"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/bitblit.c"],"versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"a10cede006f9614b465cf25609a8753efbfd45cc","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"0998a6cb232674408a03e8561dc15aa266b2f53b","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"db5c9a162d2f42bcc842b76b3d935dcc050a0eec","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"c12003bf91fdff381c55ef54fef3e961a5af2545","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"9ba1a7802ca9a2590cef95b253e6526f4364477f","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"901f44227072be60812fe8083e83e1533c04eed1","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"efaf89a75a29b2d179bf4fe63ca62852e93ad620","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"18c4ef4e765a798b47980555ed665d78b71aeadf","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/video/fbdev/core/bitblit.c"],"versions":[{"version":"2.6.12","status":"affected"},{"version":"0","lessThan":"2.6.12","status":"unaffected","versionType":"semver"},{"version":"5.4.302","lessThanOrEqual":"5.4.*","status":"unaffected","versionType":"semver"},{"version":"5.10.247","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.197","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.159","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.117","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.58","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.17.8","lessThanOrEqual":"6.17.*","status":"unaffected","versionType":"semver"},{"version":"6.18","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":"2.6.12","versionEndExcluding":"5.4.302"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.10.247"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.15.197"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.1.159"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.6.117"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.12.58"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.17.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.18"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/a10cede006f9614b465cf25609a8753efbfd45cc"},{"url":"https://git.kernel.org/stable/c/0998a6cb232674408a03e8561dc15aa266b2f53b"},{"url":"https://git.kernel.org/stable/c/db5c9a162d2f42bcc842b76b3d935dcc050a0eec"},{"url":"https://git.kernel.org/stable/c/c12003bf91fdff381c55ef54fef3e961a5af2545"},{"url":"https://git.kernel.org/stable/c/9ba1a7802ca9a2590cef95b253e6526f4364477f"},{"url":"https://git.kernel.org/stable/c/901f44227072be60812fe8083e83e1533c04eed1"},{"url":"https://git.kernel.org/stable/c/efaf89a75a29b2d179bf4fe63ca62852e93ad620"},{"url":"https://git.kernel.org/stable/c/18c4ef4e765a798b47980555ed665d78b71aeadf"}],"title":"fbdev: bitblit: bound-check glyph index in bit_putcs*","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-16T19:33:40.857434Z","id":"CVE-2025-40322","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-06-16T19:34:17.887Z"}}]}}