CVE-2026-23266

Kernel crash via unchecked clock divisor

Published Mar 18, 2026 · Updated Mar 18, 2026

Divide by zero in the rivafb driver in Linux Kernel allows local users to crash the kernel via a framebuffer mode-setting ioctl. The nv3_arb function uses state->mclk_khz, derived from the device PRAMDAC MCLK PLL, as the gns calculation divisor without first rejecting zero. Reaching the fault requires local ioctl access and a crafted or misconfigured RIVA NV3 PCI device that supplies a zero clock value; the resulting divide error stops the entire kernel.

CVSS severity5.5
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Divide by zero in the rivafb driver in Linux Kernel allows local users to crash the kernel via a framebuffer mode-setting ioctl. The nv3_arb function uses state->mclk_khz, derived from the device PRAMDAC MCLK PLL, as the gns calculation divisor without first rejecting zero. Reaching the fault requires local ioctl access and a crafted or misconfigured RIVA NV3 PCI device that supplies a zero clock value; the resulting divide error stops the entire kernel.

The record

CVE
CVE-2026-23266
Published
Mar 18, 2026
Updated
Mar 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-369, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <0209e21e3c372fa2da04c39214bec0b64e4eb5f4
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3e4cbd1d46c246dfa684c8e9d8c20ae0b960c50a
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <526460a96c5443e2fc0fd231edd1f9c49d2de26b
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <52916878db2b8e3769743a94484729f0844352df
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <73f0391e92d404da68f7484e57c106c5e673dc7e
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <78daf5984d96edec3b920c72a93bd6821b8710b7
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9efa0dc46270a8723c158c64afbcf1dead72b28c
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ec5a58f4fd581875593ea92a65485e1906a53c0f
  9. Affected versionversion=2.6.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <0209e21e3c372fa2da04c39214bec0b64e4eb5f4; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3e4cbd1d46c246dfa684c8e9d8c20ae0b960c50a; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <526460a96c5443e2fc0fd231edd1f9c49d2de26b; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <52916878db2b8e3769743a94484729f0844352df; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <73f0391e92d404da68f7484e57c106c5e673dc7e; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <78daf5984d96edec3b920c72a93bd6821b8710b7; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9efa0dc46270a8723c158c64afbcf1dead72b28c; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ec5a58f4fd581875593ea92a65485e1906a53c0f; version=2.6.12

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5Canonical UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-369Divide By Zero
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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