CVE-2009-5023

What it is

The (1) dshield.conf, (2) mail-buffered.conf, (3) mynetwatchman.conf, and (4) mynetwatchman.conf actions in action.d/ in Fail2ban before 0.8.5 allows local users to write to arbitrary files via a symlink attack on temporary files with predictable names, as demonstrated by /tmp/fail2ban-mail.txt.

At a glance

Exploitability

Can be exploited locally on the machine without logging in. High risk of data tampering.

Exploit odds

0.3% 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. 2014-06-10 14:55 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-16 23:14 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.3% in the next 30 days (EPSS).
• Severity: 4.7 MEDIUM (CVSS).
• Fix: none linked yet, which raises it.

Details

Published

2014-06-10 14:55 UTC

Last modified

2026-06-16 23:14 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-59

Record status

Modified

Affected

• fail2ban ≤ 0.8.4
• fail2ban 0.1.0
• fail2ban 0.1.1
• fail2ban 0.1.2
• fail2ban 0.3.0
• fail2ban 0.3.1
• fail2ban 0.4.0
• fail2ban 0.4.1

Attack profile CVSS 2.0 · 4.7

Attack vector

Local

Complexity

Medium

Authentication

None

Confidentiality

None

Integrity

Complete

Availability

None

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-2009-5023.md and follow it. Check whether this project is affected by CVE-2009-5023. 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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