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Linux KernelOperating system · Linux

CVE-2026-23266

MEDIUM · 5.5 CVSS v3.1 Published 2026-03-18
Fix available
A fix is available. Upgrade to 5.10.251 / 5.15.201 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 2.6.12.1, < 5.10.251>= 5.11, < 5.15.201>= 5.16, < 6.1.164>= 6.2, < 6.6.127>= 6.7, < 6.12.74>= 6.13, < 6.18.13>= 6.19, < 6.19.3= 2.6.12

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.10.251 / 5.15.201 / 6.1.164 or later
Fixed in 5.10.2515.15.2016.1.164
Vendor patch git.kernel.org →
Recommended fix High confidence

6.1.164 (or later 6.1.y LTS, 6.6.127+ for 6.6.y, 5.15.201+ for 5.15.y, or 5.10.251+ for 5.10.y)

  1. 1. Identify the currently running kernel version using `uname -r`
  2. 2. Check if the system is running an affected kernel version (>= 2.6.12.1 and < 5.10.251, >= 5.11 and < 5.15.201, >= 5.16 and < 6.1.164, or >= 6.2 and < 6.6.127)
  3. 3. Upgrade the Linux kernel to version 6.1.164 or later (6.6.127 or later for the 6.6.y branch, 5.15.201 or later for the 5.15.y branch, or 5.10.251 or later for the 5.10.y branch)
  4. 4. Update boot loader configuration if necessary to ensure the new kernel is selected on next boot
  5. 5. Reboot the system into the patched kernel
  6. 6. Verify the fix is applied by checking the kernel version with `uname -r` and confirming the rivafb driver loads without the divide error
Caveat Kernel upgrades may require matching kernel modules and could introduce minor behavior changes; ensure dependent modules and drivers are compatible with the new kernel version

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-23266 in production — separate from our analysis above.

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