{"id":"CVE-2026-23266","state":"PUBLISHED","title":"fbdev: rivafb: fix divide error in nv3_arb()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: rivafb: fix divide error in nv3_arb()\n\nA userspace program can trigger the RIVA NV3 arbitration code by calling\nthe FBIOPUT_VSCREENINFO ioctl on /dev/fb*. When doing so, the driver\nrecomputes FIFO arbitration parameters in nv3_arb(), using state->mclk_khz\n(derived from the PRAMDAC MCLK PLL) as a divisor without validating it\nfirst.\n\nIn a normal setup, state->mclk_khz is provided by the real hardware and is\nnon-zero. However, an attacker can construct a malicious or misconfigured\ndevice (e.g. a crafted/emulated PCI device) that exposes a bogus PLL\nconfiguration, causing state->mclk_khz to become zero.  Once\nnv3_get_param() calls nv3_arb(), the division by state->mclk_khz in the gns\ncalculation causes a divide error and crashes the kernel.\n\nFix this by checking whether state->mclk_khz is zero and bailing out before\ndoing the division.\n\nThe following log reveals it:\n\nrivafb: setting virtual Y resolution to 2184\ndivide error: 0000 [#1] PREEMPT SMP KASAN PTI\nCPU: 0 PID: 2187 Comm: syz-executor.0 Not tainted 5.18.0-rc1+ #1\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014\nRIP: 0010:nv3_arb drivers/video/fbdev/riva/riva_hw.c:439 [inline]\nRIP: 0010:nv3_get_param+0x3ab/0x13b0 drivers/video/fbdev/riva/riva_hw.c:546\nCall Trace:\n  nv3CalcArbitration.constprop.0+0x255/0x460 drivers/video/fbdev/riva/riva_hw.c:603\n  nv3UpdateArbitrationSettings drivers/video/fbdev/riva/riva_hw.c:637 [inline]\n  CalcStateExt+0x447/0x1b90 drivers/video/fbdev/riva/riva_hw.c:1246\n  riva_load_video_mode+0x8a9/0xea0 drivers/video/fbdev/riva/fbdev.c:779\n  rivafb_set_par+0xc0/0x5f0 drivers/video/fbdev/riva/fbdev.c:1196\n  fb_set_var+0x604/0xeb0 drivers/video/fbdev/core/fbmem.c:1033\n  do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1109\n  fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1188\n  __x64_sys_ioctl+0x122/0x190 fs/ioctl.c:856","publishedAt":"2026-03-18T17:44:48.715Z","updatedAt":"2026-05-11T22:03:32.226Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"ec5a58f4fd581875593ea92a65485e1906a53c0f","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"52916878db2b8e3769743a94484729f0844352df","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"526460a96c5443e2fc0fd231edd1f9c49d2de26b","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"78daf5984d96edec3b920c72a93bd6821b8710b7","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"9efa0dc46270a8723c158c64afbcf1dead72b28c","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"3e4cbd1d46c246dfa684c8e9d8c20ae0b960c50a","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"73f0391e92d404da68f7484e57c106c5e673dc7e","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"0209e21e3c372fa2da04c39214bec0b64e4eb5f4","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/video/fbdev/riva/riva_hw.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.12","versionType":"semver"},{"version":"5.10.251","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.201","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.164","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.127","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.74","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.13","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.3","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/video/fbdev/riva/riva_hw.c"]}],"references":["https://git.kernel.org/stable/c/ec5a58f4fd581875593ea92a65485e1906a53c0f","https://git.kernel.org/stable/c/52916878db2b8e3769743a94484729f0844352df","https://git.kernel.org/stable/c/526460a96c5443e2fc0fd231edd1f9c49d2de26b","https://git.kernel.org/stable/c/78daf5984d96edec3b920c72a93bd6821b8710b7","https://git.kernel.org/stable/c/9efa0dc46270a8723c158c64afbcf1dead72b28c","https://git.kernel.org/stable/c/3e4cbd1d46c246dfa684c8e9d8c20ae0b960c50a","https://git.kernel.org/stable/c/73f0391e92d404da68f7484e57c106c5e673dc7e","https://git.kernel.org/stable/c/0209e21e3c372fa2da04c39214bec0b64e4eb5f4"],"weaknesses":[],"ingestedAt":"2026-10-29T20:11:21.040Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/23xxx/CVE-2026-23266.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-23266","state":"PUBLISHED","datePublished":"2026-03-18T17:44:48.715Z","dateUpdated":"2026-05-11T22:03:32.226Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-01-13T15:37:45.991Z"},"containers":{"cna":{"title":"fbdev: rivafb: fix divide error in nv3_arb()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: rivafb: fix divide error in nv3_arb()\n\nA userspace program can trigger the RIVA NV3 arbitration code by calling\nthe FBIOPUT_VSCREENINFO ioctl on /dev/fb*. When doing so, the driver\nrecomputes FIFO arbitration parameters in nv3_arb(), using state->mclk_khz\n(derived from the PRAMDAC MCLK PLL) as a divisor without validating it\nfirst.\n\nIn a normal setup, state->mclk_khz is provided by the real hardware and is\nnon-zero. However, an attacker can construct a malicious or misconfigured\ndevice (e.g. a crafted/emulated PCI device) that exposes a bogus PLL\nconfiguration, causing state->mclk_khz to become zero.  Once\nnv3_get_param() calls nv3_arb(), the division by state->mclk_khz in the gns\ncalculation causes a divide error and crashes the kernel.\n\nFix this by checking whether state->mclk_khz is zero and bailing out before\ndoing the division.\n\nThe following log reveals it:\n\nrivafb: setting virtual Y resolution to 2184\ndivide error: 0000 [#1] PREEMPT SMP KASAN PTI\nCPU: 0 PID: 2187 Comm: syz-executor.0 Not tainted 5.18.0-rc1+ #1\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014\nRIP: 0010:nv3_arb drivers/video/fbdev/riva/riva_hw.c:439 [inline]\nRIP: 0010:nv3_get_param+0x3ab/0x13b0 drivers/video/fbdev/riva/riva_hw.c:546\nCall Trace:\n  nv3CalcArbitration.constprop.0+0x255/0x460 drivers/video/fbdev/riva/riva_hw.c:603\n  nv3UpdateArbitrationSettings drivers/video/fbdev/riva/riva_hw.c:637 [inline]\n  CalcStateExt+0x447/0x1b90 drivers/video/fbdev/riva/riva_hw.c:1246\n  riva_load_video_mode+0x8a9/0xea0 drivers/video/fbdev/riva/fbdev.c:779\n  rivafb_set_par+0xc0/0x5f0 drivers/video/fbdev/riva/fbdev.c:1196\n  fb_set_var+0x604/0xeb0 drivers/video/fbdev/core/fbmem.c:1033\n  do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1109\n  fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1188\n  __x64_sys_ioctl+0x122/0x190 fs/ioctl.c:856"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"ec5a58f4fd581875593ea92a65485e1906a53c0f","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"52916878db2b8e3769743a94484729f0844352df","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"526460a96c5443e2fc0fd231edd1f9c49d2de26b","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"78daf5984d96edec3b920c72a93bd6821b8710b7","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"9efa0dc46270a8723c158c64afbcf1dead72b28c","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"3e4cbd1d46c246dfa684c8e9d8c20ae0b960c50a","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"73f0391e92d404da68f7484e57c106c5e673dc7e","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"0209e21e3c372fa2da04c39214bec0b64e4eb5f4","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/video/fbdev/riva/riva_hw.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.12","versionType":"semver"},{"version":"5.10.251","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.201","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.164","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.127","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.74","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.13","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.3","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/video/fbdev/riva/riva_hw.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/ec5a58f4fd581875593ea92a65485e1906a53c0f"},{"url":"https://git.kernel.org/stable/c/52916878db2b8e3769743a94484729f0844352df"},{"url":"https://git.kernel.org/stable/c/526460a96c5443e2fc0fd231edd1f9c49d2de26b"},{"url":"https://git.kernel.org/stable/c/78daf5984d96edec3b920c72a93bd6821b8710b7"},{"url":"https://git.kernel.org/stable/c/9efa0dc46270a8723c158c64afbcf1dead72b28c"},{"url":"https://git.kernel.org/stable/c/3e4cbd1d46c246dfa684c8e9d8c20ae0b960c50a"},{"url":"https://git.kernel.org/stable/c/73f0391e92d404da68f7484e57c106c5e673dc7e"},{"url":"https://git.kernel.org/stable/c/0209e21e3c372fa2da04c39214bec0b64e4eb5f4"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T22:03:32.226Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.10.251"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.15.201"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.1.164"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.6.127"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.12.74"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.18.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.19.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}