How severe is CVE-2008-4109?

CVE-2008-4109 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-2008-4109 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 29% (98th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2008-4109?

CVE-2008-4109 primarily affects Openbsd Openssh. In total, 67 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2008-4109?

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

When was CVE-2008-4109 published?

CVE-2008-4109 was published on 2008-09-18 and last updated on 2026-06-16.

CVE-2008-4109

CVE-2008-4109 is a medium-severity vulnerability in Openbsd Openssh with a CVSS 2.0 base score of 5.0. Its EPSS exploit-prediction score of 29% places it in the 98th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-264.

Key facts

Severity: Medium (CVSS 2.0 base score 5.0)
EPSS exploit prediction: 29% (98th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-264
Affected product: Openbsd Openssh
Published: 2008-09-18
Last modified: 2026-06-16

Description

A certain Debian patch for OpenSSH before 4.3p2-9etch3 on etch; before 4.6p1-1 on sid and lenny; and on other distributions such as SUSE uses functions that are not async-signal-safe in the signal handler for login timeouts, which allows remote attackers to cause a denial of service (connection slot exhaustion) via multiple login attempts. NOTE: this issue exists because of an incorrect fix for CVE-2006-5051.

Frequently asked questions

What is CVE-2008-4109?: A certain Debian patch for OpenSSH before 4.3p2-9etch3 on etch; before 4.6p1-1 on sid and lenny; and on other distributions such as SUSE uses functions that are not async-signal-safe in the signal handler for login timeouts, which allows remote attackers to cause a denial of service (connection slot exhaustion) via multiple login attempts. NOTE: this issue exists because of an incorrect fix for CVE-2006-5051.
How severe is CVE-2008-4109?: CVE-2008-4109 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-2008-4109 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 29% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2008-4109?: CVE-2008-4109 primarily affects Openbsd Openssh. In total, 67 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2008-4109?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2008-4109 published?: CVE-2008-4109 was published on 2008-09-18 and last updated on 2026-06-16.

References

Affected products (67)

cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:1.2:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:1.2.1:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:1.2.2:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:1.2.3:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:1.2.27:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:1.3:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:1.5:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:1.5.7:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:1.5.8:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:2:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:2.1:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:2.1.1:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:2.2:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:2.3:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:2.3.1:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:2.5:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:2.5.1:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:2.5.2:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:2.9:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:2.9.9:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:2.9.9p2:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:2.9p1:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:2.9p2:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:3.0:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:3.0.1:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:3.0.1p1:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:3.0.2:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:3.0.2p1:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:3.0p1:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:3.1:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:3.1p1:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:3.2:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:3.2.2:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:3.2.2p1:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:3.2.3p1:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:3.3:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:3.3p1:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:3.4:*:*:*:*:*:*:*
cpe:2.3:a:openbsd:openssh:3.4p1:*:*:*:*:*:*:*

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Browse all CWE-264 (Permissions, Privileges, and Access Controls) vulnerabilities →

Threat intelligence

Threat-intel indicators referencing this CVE:

60.166.8.174 (ipv4-addr)
60.166.31.198 (ipv4-addr)
112.31.93.229 (ipv4-addr)
61.191.145.123 (ipv4-addr)
60.29.128.122 (ipv4-addr)
223.82.97.51 (ipv4-addr)
183.6.115.88 (ipv4-addr)
175.203.199.118 (ipv4-addr)