How severe is CVE-2009-5023?

CVE-2009-5023 has a CVSS 2.0 base score of 4.7, rated medium severity.

Is CVE-2009-5023 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2009-5023?

CVE-2009-5023 primarily affects Fail2ban. In total, 30 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2009-5023?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2009-5023 published?

CVE-2009-5023 was published on 2014-06-10 and last updated on 2026-06-16.

CVE-2009-5023

CVE-2009-5023 is a medium-severity vulnerability in Fail2ban with a CVSS 2.0 base score of 4.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-59.

Key facts

Severity: Medium (CVSS 2.0 base score 4.7)
EPSS exploit prediction: 0% (26th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-59
Affected product: Fail2ban
Published: 2014-06-10
Last modified: 2026-06-16

Description

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.

Frequently asked questions

What is CVE-2009-5023?: 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.
How severe is CVE-2009-5023?: CVE-2009-5023 has a CVSS 2.0 base score of 4.7, rated medium severity.
Is CVE-2009-5023 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-5023?: CVE-2009-5023 primarily affects Fail2ban. In total, 30 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-5023?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2009-5023 published?: CVE-2009-5023 was published on 2014-06-10 and last updated on 2026-06-16.

References

Affected products (30)

cpe:2.3:a:fail2ban:fail2ban:*:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.1.0:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.1.1:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.1.2:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.3.0:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.3.1:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.4.0:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.4.1:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.5.0:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.5.1:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.5.2:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.5.3:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.5.4:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.5.5:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.6.0:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.6.1:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.7.0:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.7.1:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.7.2:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.7.3:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.7.4:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.7.5:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.7.6:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.7.7:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.7.8:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.7.9:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.8.0:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.8.1:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.8.2:*:*:*:*:*:*:*
cpe:2.3:a:fail2ban:fail2ban:0.8.3:*:*:*:*:*:*:*

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