{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-23266",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2026-23266"
  ],
  "published": "2026-03-18T17:45:43Z",
  "summary": "fbdev: rivafb: fix divide error in nv3_arb()",
  "details": "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": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.164",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-23266"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ec5a58f4fd581875593ea92a65485e1906a53c0f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/52916878db2b8e3769743a94484729f0844352df"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/526460a96c5443e2fc0fd231edd1f9c49d2de26b"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/78daf5984d96edec3b920c72a93bd6821b8710b7"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9efa0dc46270a8723c158c64afbcf1dead72b28c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/3e4cbd1d46c246dfa684c8e9d8c20ae0b960c50a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/73f0391e92d404da68f7484e57c106c5e673dc7e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/0209e21e3c372fa2da04c39214bec0b64e4eb5f4"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-05-12T04:54:46Z"
  }
}