CVE-2026-23266 (GCVE-0-2026-23266)

Vulnerability from cvelistv5 – Published: 2026-03-18 17:44 – Updated: 2026-03-18 17:44
VLAI?
Title
fbdev: rivafb: fix divide error in nv3_arb()
Summary
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
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < ec5a58f4fd581875593ea92a65485e1906a53c0f (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 52916878db2b8e3769743a94484729f0844352df (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 526460a96c5443e2fc0fd231edd1f9c49d2de26b (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 78daf5984d96edec3b920c72a93bd6821b8710b7 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 9efa0dc46270a8723c158c64afbcf1dead72b28c (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 3e4cbd1d46c246dfa684c8e9d8c20ae0b960c50a (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 73f0391e92d404da68f7484e57c106c5e673dc7e (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 0209e21e3c372fa2da04c39214bec0b64e4eb5f4 (git)
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    Linux Linux Affected: 2.6.12
Unaffected: 0 , < 2.6.12 (semver)
Unaffected: 5.10.251 , ≤ 5.10.* (semver)
Unaffected: 5.15.201 , ≤ 5.15.* (semver)
Unaffected: 6.1.164 , ≤ 6.1.* (semver)
Unaffected: 6.6.127 , ≤ 6.6.* (semver)
Unaffected: 6.12.74 , ≤ 6.12.* (semver)
Unaffected: 6.18.13 , ≤ 6.18.* (semver)
Unaffected: 6.19.3 , ≤ 6.19.* (semver)
Unaffected: 7.0-rc1 , ≤ * (original_commit_for_fix)
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{
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              "version": "5.15.201",
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      "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-\u003emclk_khz\n(derived from the PRAMDAC MCLK PLL) as a divisor without validating it\nfirst.\n\nIn a normal setup, state-\u003emclk_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-\u003emclk_khz to become zero.  Once\nnv3_get_param() calls nv3_arb(), the division by state-\u003emclk_khz in the gns\ncalculation causes a divide error and crashes the kernel.\n\nFix this by checking whether state-\u003emclk_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"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-18T17:44:48.715Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "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"
        },
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          "url": "https://git.kernel.org/stable/c/3e4cbd1d46c246dfa684c8e9d8c20ae0b960c50a"
        },
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          "url": "https://git.kernel.org/stable/c/73f0391e92d404da68f7484e57c106c5e673dc7e"
        },
        {
          "url": "https://git.kernel.org/stable/c/0209e21e3c372fa2da04c39214bec0b64e4eb5f4"
        }
      ],
      "title": "fbdev: rivafb: fix divide error in nv3_arb()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23266",
    "datePublished": "2026-03-18T17:44:48.715Z",
    "dateReserved": "2026-01-13T15:37:45.991Z",
    "dateUpdated": "2026-03-18T17:44:48.715Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-23266\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-03-18T18:16:25.370\",\"lastModified\":\"2026-03-19T13:25:00.570\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"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-\u003emclk_khz\\n(derived from the PRAMDAC MCLK PLL) as a divisor without validating it\\nfirst.\\n\\nIn a normal setup, state-\u003emclk_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-\u003emclk_khz to become zero.  Once\\nnv3_get_param() calls nv3_arb(), the division by state-\u003emclk_khz in the gns\\ncalculation causes a divide error and crashes the kernel.\\n\\nFix this by checking whether state-\u003emclk_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\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0209e21e3c372fa2da04c39214bec0b64e4eb5f4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/3e4cbd1d46c246dfa684c8e9d8c20ae0b960c50a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/526460a96c5443e2fc0fd231edd1f9c49d2de26b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/52916878db2b8e3769743a94484729f0844352df\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/73f0391e92d404da68f7484e57c106c5e673dc7e\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/78daf5984d96edec3b920c72a93bd6821b8710b7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/9efa0dc46270a8723c158c64afbcf1dead72b28c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ec5a58f4fd581875593ea92a65485e1906a53c0f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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