CVE-2026-74320

Kernel crash via unchecked sm501fb mode copy

Published Aug 15, 2026 · Updated Aug 15, 2026

Buffer overflow in Linux sm501fb from 2.6.39 allows local users to crash the kernel through an oversized Open Firmware mode string. The mode parser overwrites a static or module-parameter buffer without checking the property length, while dual CRT and PANEL setup also reuses and double-frees edid_data. The faulty path requires an SM501 framebuffer configured through Open Firmware; successful triggering interrupts the host by crashing the kernel.

CVSS severity5.5
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in Linux sm501fb from 2.6.39 allows local users to crash the kernel through an oversized Open Firmware mode string. The mode parser overwrites a static or module-parameter buffer without checking the property length, while dual CRT and PANEL setup also reuses and double-frees edid_data. The faulty path requires an SM501 framebuffer configured through Open Firmware; successful triggering interrupts the host by crashing the kernel.

The record

CVE
CVE-2026-74320
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-120, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 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=2.6.39
  2. Affected versionversion=4295f9bf74a885da390abc49a3b42a011c1bb890 <0bc3d909a49e1fd8b8c3f2160d526e672c40621d
  3. Affected versionversion=4295f9bf74a885da390abc49a3b42a011c1bb890 <47008d59c60ed896085da95f8d4dd40e1677dd3a
  4. Affected versionversion=4295f9bf74a885da390abc49a3b42a011c1bb890 <48cf0f4c6581ec90104cec9c5bf794a8bf347e30
  5. Affected versionversion=4295f9bf74a885da390abc49a3b42a011c1bb890 <9057e3f5db39f0ef0dac2f59f2bc59bf17e36c31
  6. Affected versionversion=4295f9bf74a885da390abc49a3b42a011c1bb890 <b2ff450f7f5cfc7143cab57c3ad70293ba8b822a
  7. Affected versionversion=4295f9bf74a885da390abc49a3b42a011c1bb890 <d374f76e1257ecc5d691a765c512ed2c29a44741
  8. Affected versionversion=4295f9bf74a885da390abc49a3b42a011c1bb890 <d8421e09382cfe0bd2a044c8b0a822f64855dd4e
  9. Affected versionversion=4295f9bf74a885da390abc49a3b42a011c1bb890 <de590cdf7efec8a0b6da90ae2ab5fc5df26810b9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.39; version=4295f9bf74a885da390abc49a3b42a011c1bb890 <0bc3d909a49e1fd8b8c3f2160d526e672c40621d; version=4295f9bf74a885da390abc49a3b42a011c1bb890 <47008d59c60ed896085da95f8d4dd40e1677dd3a; version=4295f9bf74a885da390abc49a3b42a011c1bb890 <48cf0f4c6581ec90104cec9c5bf794a8bf347e30; version=4295f9bf74a885da390abc49a3b42a011c1bb890 <9057e3f5db39f0ef0dac2f59f2bc59bf17e36c31; version=4295f9bf74a885da390abc49a3b42a011c1bb890 <b2ff450f7f5cfc7143cab57c3ad70293ba8b822a; version=4295f9bf74a885da390abc49a3b42a011c1bb890 <d374f76e1257ecc5d691a765c512ed2c29a44741; version=4295f9bf74a885da390abc49a3b42a011c1bb890 <d8421e09382cfe0bd2a044c8b0a822f64855dd4e; version=4295f9bf74a885da390abc49a3b42a011c1bb890 <de590cdf7efec8a0b6da90ae2ab5fc5df26810b9

Published CVSS scores

5.5Red HatCVSS: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499Endpoint Denial of Service

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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