CVE-2009-4016

CVE-2009-4016 is a medium-severity vulnerability in Ircd-hybrid with a CVSS 2.0 base score of 6.8. 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-189.

Key facts

Description

Integer underflow in the clean_string function in irc_string.c in (1) IRCD-hybrid 7.2.2 and 7.2.3, (2) ircd-ratbox before 2.2.9, and (3) oftc-hybrid before 1.6.8, when flatten_links is disabled, allows remote attackers to execute arbitrary code or cause a denial of service (daemon crash) via a LINKS command.

Frequently asked questions

What is CVE-2009-4016?
Integer underflow in the clean_string function in irc_string.c in (1) IRCD-hybrid 7.2.2 and 7.2.3, (2) ircd-ratbox before 2.2.9, and (3) oftc-hybrid before 1.6.8, when flatten_links is disabled, allows remote attackers to execute arbitrary code or cause a denial of service (daemon crash) via a LINKS command.
How severe is CVE-2009-4016?
CVE-2009-4016 has a CVSS 2.0 base score of 6.8, rated medium severity.
Is CVE-2009-4016 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-4016?
CVE-2009-4016 primarily affects Ircd-hybrid. In total, 74 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-4016?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2009-4016 published?
CVE-2009-4016 was published on 2010-02-04 and last updated on 2026-06-16.

References

Affected products (74)

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