CVE-2009-3939

What it is

The poll_mode_io file for the megaraid_sas driver in the Linux kernel 2.6.31.6 and earlier has world-writable permissions, which allows local users to change the I/O mode of the driver by modifying this file.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of data tampering, service disruption.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2009-11-16 19:30 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-16 23:12 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.4% in the next 30 days (EPSS).
• Severity: 7.1 HIGH (CVSS).
• Fix: none linked yet, which raises it.

Details

Published

2009-11-16 19:30 UTC

Last modified

2026-06-16 23:12 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-732 · Incorrect permission assignment

Record status

Modified

Affected

• Linux Kernel ≤ 2.6.31.6
• Redhat Virtualization 5
• Redhat Enterprise Linux Desktop 5.0
• Redhat Enterprise Linux Eus 5.4
• Redhat Enterprise Linux Server 5.0
• Redhat Enterprise Linux Workstation 5.0
• Canonical Ubuntu Linux 6.06
• Canonical Ubuntu Linux 8.04

Attack profile CVSS 3.1 · 7.1

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2009-3939.md and follow it. Check whether this project is affected by CVE-2009-3939. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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