cbcvebase.
CVE-2026-23266
published 2026-03-18

CVE-2026-23266: In the Linux kernel, the following vulnerability has been resolved: fbdev: rivafb: fix divide error in nv3_arb() A userspace program can trigger the RIVA NV3…

PriorityP421medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.11%
1.7th percentile
In the Linux kernel, the following vulnerability has been resolved: fbdev: rivafb: fix divide error in nv3_arb() A userspace program can trigger the RIVA NV3 arbitration code by calling the FBIOPUT_VSCREENINFO ioctl on /dev/fb*. When doing so, the driver recomputes FIFO arbitration parameters in nv3_arb(), using state->mclk_khz (derived from the PRAMDAC MCLK PLL) as a divisor without validating it first. In a normal setup, state->mclk_khz is provided by the real hardware and is non-zero. However, an attacker can construct a malicious or misconfigured device (e.g. a crafted/emulated PCI device) that exposes a bogus PLL configuration, causing state->mclk_khz to become zero. Once nv3_get_param() calls nv3_arb(), the division by state->mclk_khz in the gns calculation causes a divide error and crashes the kernel. Fix this by checking whether state->mclk_khz is zero and bailing out before doing the division. The following log reveals it: rivafb: setting virtual Y resolution to 2184 divide error: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 0 PID: 2187 Comm: syz-executor.0 Not tainted 5.18.0-rc1+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 RIP: 0010:nv3_arb drivers/video/fbdev/riva/riva_hw.c:439 [inline] RIP: 0010:nv3_get_param+0x3ab/0x13b0 drivers/video/fbdev/riva/riva_hw.c:546 Call Trace: nv3CalcArbitration.constprop.0+0x255/0x460 drivers/video/fbdev/riva/riva_hw.c:603 nv3UpdateArbitrationSettings drivers/video/fbdev/riva/riva_hw.c:637 [inline] CalcStateExt+0x447/0x1b90 drivers/video/fbdev/riva/riva_hw.c:1246 riva_load_video_mode+0x8a9/0xea0 drivers/video/fbdev/riva/fbdev.c:779 rivafb_set_par+0xc0/0x5f0 drivers/video/fbdev/riva/fbdev.c:1196 fb_set_var+0x604/0xeb0 drivers/video/fbdev/core/fbmem.c:1033 do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1188 __x64_sys_ioctl+0x122/0x190 fs/ioctl.c:856

Affected

72 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.1.164-1 (bookworm)linux 6.1.164-1 (bookworm)
linuxlinux
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ec5a58f4fd581875593ea92a65485e1906a53c0fec5a58f4fd581875593ea92a65485e1906a53c0f
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 52916878db2b8e3769743a94484729f0844352df52916878db2b8e3769743a94484729f0844352df
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 526460a96c5443e2fc0fd231edd1f9c49d2de26b526460a96c5443e2fc0fd231edd1f9c49d2de26b
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 78daf5984d96edec3b920c72a93bd6821b8710b778daf5984d96edec3b920c72a93bd6821b8710b7
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 9efa0dc46270a8723c158c64afbcf1dead72b28c9efa0dc46270a8723c158c64afbcf1dead72b28c
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3e4cbd1d46c246dfa684c8e9d8c20ae0b960c50a3e4cbd1d46c246dfa684c8e9d8c20ae0b960c50a
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 73f0391e92d404da68f7484e57c106c5e673dc7e73f0391e92d404da68f7484e57c106c5e673dc7e
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 0209e21e3c372fa2da04c39214bec0b64e4eb5f40209e21e3c372fa2da04c39214bec0b64e4eb5f4
linuxlinux_kernel
linuxlinux_kernel>= 0 < 5.10.251-15.10.251-1
linuxlinux_kernel>= 0 < 6.1.164-16.1.164-1
linuxlinux_kernel>= 0 < 6.12.74-16.12.74-1
linuxlinux_kernel>= 0 < 6.18.13-16.18.13-1
linuxlinux_kernel>= 2.6.12 < 5.10.2515.10.251
linuxlinux_kernel>= 2.6.12.1 < 5.10.2515.10.251
linuxlinux_kernel>= 5.11 < 5.15.2015.15.201
linuxlinux_kernel>= 5.11.0 < 5.15.2015.15.201
linuxlinux_kernel>= 5.16 < 6.1.1646.1.164
linuxlinux_kernel>= 5.16.0 < 6.1.1646.1.164
linuxlinux_kernel>= 6.13 < 6.18.136.18.13
linuxlinux_kernel>= 6.13.0 < 6.18.136.18.13
linuxlinux_kernel>= 6.19 < 6.19.36.19.3
linuxlinux_kernel>= 6.19.0 < 6.19.36.19.3

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
vendor_ubuntu8.8HIGH
vendor_msrc5.5MEDIUM
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