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

No CVSS v4.0

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Linux Linux unaffected
Version Status Constraints
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 affected
< ec5a58f4fd581875593ea92a65485e1906a53c0f
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 affected
< 52916878db2b8e3769743a94484729f0844352df
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 affected
< 526460a96c5443e2fc0fd231edd1f9c49d2de26b
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 affected
< 78daf5984d96edec3b920c72a93bd6821b8710b7
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 affected
< 9efa0dc46270a8723c158c64afbcf1dead72b28c
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 affected
< 3e4cbd1d46c246dfa684c8e9d8c20ae0b960c50a
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 affected
< 73f0391e92d404da68f7484e57c106c5e673dc7e
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 affected
< 0209e21e3c372fa2da04c39214bec0b64e4eb5f4
Linux Linux affected
Version Status Constraints
2.6.12 affected
—
0 unaffected
< 2.6.12
5.10.251 unaffected
≤ 5.10.*
5.15.201 unaffected
≤ 5.15.*
6.1.164 unaffected
≤ 6.1.*
6.6.127 unaffected
≤ 6.6.*
6.12.74 unaffected
≤ 6.12.*
6.18.13 unaffected
≤ 6.18.*
6.19.3 unaffected
≤ 6.19.*
7.0-rc1 unaffected
≤ *

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References
Link Providers
https://git.kernel.org/stable/c/0209e21e3c372fa2da04c39214bec0b64e4eb5f4 cve-icon cve-icon
https://git.kernel.org/stable/c/3e4cbd1d46c246dfa684c8e9d8c20ae0b960c50a cve-icon cve-icon
https://git.kernel.org/stable/c/526460a96c5443e2fc0fd231edd1f9c49d2de26b cve-icon cve-icon
https://git.kernel.org/stable/c/52916878db2b8e3769743a94484729f0844352df cve-icon cve-icon
https://git.kernel.org/stable/c/73f0391e92d404da68f7484e57c106c5e673dc7e cve-icon cve-icon
https://git.kernel.org/stable/c/78daf5984d96edec3b920c72a93bd6821b8710b7 cve-icon cve-icon
https://git.kernel.org/stable/c/9efa0dc46270a8723c158c64afbcf1dead72b28c cve-icon cve-icon
https://git.kernel.org/stable/c/ec5a58f4fd581875593ea92a65485e1906a53c0f cve-icon cve-icon
https://lore.kernel.org/linux-cve-announce/2026031853-CVE-2026-23266-b57b@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-23266 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-23266 cve-icon
History

Thu, 19 Mar 2026 00:15:00 +0000

Type Values Removed Values Added
References

Wed, 18 Mar 2026 18:00:00 +0000

Type Values Removed Values Added
Description 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
Title fbdev: rivafb: fix divide error in nv3_arb()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-03-18T17:44:48.715Z

Reserved: 2026-01-13T15:37:45.991Z

Link: CVE-2026-23266

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-03-18T18:16:25.370

Modified: 2026-03-18T18:16:25.370

Link: CVE-2026-23266

cve-icon Redhat

Severity :

Publid Date: 2026-03-18T00:00:00Z

Links: CVE-2026-23266 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.