{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98838", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.373Z", "datePublished": "2026-10-18T15:50:07.004Z", "dateUpdated": "2026-10-21T12:57:24.278Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-21T12:57:24.278Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvt: skip screen update for DEC alignment test on backgroup consoles\n\n[BUG]\nRecently, we encountered a KASAN warning as follows:\n\nBUG: KASAN: slab-out-of-bounds in fb_pad_aligned_buffer+0x11f/0x140\nRead of size 1 at addr ff1100015fd9f6a4 by task tty_fbcon_oob/1239\nCPU: 7 UID: 0 PID: 1239 Comm: tty_fbcon_oob Not tainted 7.3.0-rc1 #100 PREEMPT(full)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014\nCall Trace:\n \n ...\n kasan_report+0xf0/0x120\n fb_pad_aligned_buffer+0x11f/0x140\n ccw_putcs+0x86c/0xa80\n fbcon_putcs+0x338/0x410\n do_update_region+0x21d/0x450\n do_con_write+0x1e0e/0x4880\n con_write+0x13/0x80\n n_tty_write+0x374/0x1010\n file_tty_write.isra.0+0x404/0x7a0\n ...\n\nreproduce:\n1) open /dev/tty0, set a KDFONTOP ioctl with op.op = KD_FONT_OP_SET,\nop.width = 8 and op.height = 16 (visible VC1)\n2) open /dev/tty1, set a KDFONTOP ioctl with op.op = KD_FONT_OP_SET,\nop.width = 28 and op.height = 24 (invisible VC2)\n3) echo 3 > /sys/devices/virtual/graphics/fbcon/rotate_all\n4) write EShash8(esc hash8) to tty1\n\n[CAUSE]\nAll VCs render to the framebuffer. setfont only modifies the target VC's\nfont without resizing the framebuffer backing buffer (par->rotated.buf);\nthe buffer is only resized for the visible VC\n(fbcon_do_set_font -> ... -> vc_do_resize -> update_screen). This relies on\nthe con_should_update() check performed before every update_region().\n\nHowever, the ESC # 8 path (do_con_trol -> do_update_region) omits the\ncon_should_update() check. After changing the font size of an invisible VC,\ndo_update_region() fills using the new font size against a buffer that was\nnever resized, causing an out-of-bounds access.\n\n[FIX]\nOnly push the update when the console is visible and not blanked, add\nthe con_should_update() check in the do_con_trol() like every other call\nsite of do_update_region() (update_region(), invert_screen(), ...)." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/tty/vt/vt.c" ], "versions": [ { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "2fc4e71aefab57c80ccc9775aad2af503fc90810", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "985c000b046ca4ee11ee34ef85db500c569ef6e8", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "ad06f7312d3f615dd466483ce81a9b9619166686", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "0ee53081425a1a31ce15089012cd96b8353eb44e", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "0928ed9bd7946baee911efa401088697836e3b1e", "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/tty/vt/vt.c" ], "versions": [ { "version": "2.6.12", "status": "affected" }, { "version": "0", "lessThan": "2.6.12", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.113", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.56", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.10", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "6.6.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.12.113" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.18.56" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "7.2.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/2fc4e71aefab57c80ccc9775aad2af503fc90810" }, { "url": "https://git.kernel.org/stable/c/985c000b046ca4ee11ee34ef85db500c569ef6e8" }, { "url": "https://git.kernel.org/stable/c/ad06f7312d3f615dd466483ce81a9b9619166686" }, { "url": "https://git.kernel.org/stable/c/0ee53081425a1a31ce15089012cd96b8353eb44e" }, { "url": "https://git.kernel.org/stable/c/0928ed9bd7946baee911efa401088697836e3b1e" } ], "title": "vt: skip screen update for DEC alignment test on backgroup consoles", "x_generator": { "engine": "bippy-1.2.0" } } } }