CVE-2026-23266 (GCVE-0-2026-23266)
Vulnerability from cvelistv5
Published
2026-03-18 17:44
Modified
2026-04-13 06:03
Severity ?
VLAI Severity ?
EPSS score ?
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
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 |
||
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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": "2026-04-13T06:03:14.340Z",
"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"
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{
"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"
}
],
"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": "2026-04-13T06:03:14.340Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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