CVE-2008-4609

CVE-2008-4609 is a high-severity vulnerability in Bsd with a CVSS 2.0 base score of 7.1. Its EPSS exploit-prediction score of 32% places it in the 98th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-16.

Key facts

• Severity: High (CVSS 2.0 base score 7.1)
• EPSS exploit prediction: 32% (98th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-16
• Affected product: Bsd
• Published: 2008-10-20
• Last modified: 2026-06-16

Description

The TCP implementation in (1) Linux, (2) platforms based on BSD Unix, (3) Microsoft Windows, (4) Cisco products, and probably other operating systems allows remote attackers to cause a denial of service (connection queue exhaustion) via multiple vectors that manipulate information in the TCP state table, as demonstrated by sockstress.

Frequently asked questions

What is CVE-2008-4609?

The TCP implementation in (1) Linux, (2) platforms based on BSD Unix, (3) Microsoft Windows, (4) Cisco products, and probably other operating systems allows remote attackers to cause a denial of service (connection queue exhaustion) via multiple vectors that manipulate information in the TCP state table, as demonstrated by sockstress.

How severe is CVE-2008-4609?

CVE-2008-4609 has a CVSS 2.0 base score of 7.1, rated high severity.

Is CVE-2008-4609 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 32% (98th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2008-4609?

CVE-2008-4609 primarily affects Bsd. In total, 2046 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2008-4609?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2008-4609 published?

CVE-2008-4609 was published on 2008-10-20 and last updated on 2026-06-16.

References

• http://blog.robertlee.name/2008/10/conjecture-speculation.html
• http://insecure.org/stf/tcp-dos-attack-explained.html
• http://lists.immunitysec.com/pipermail/dailydave/2008-October/005360.html
• http://marc.info/?l=bugtraq&m=125856010926699&w=2
• http://searchsecurity.techtarget.com.au/articles/27154-TCP-is-fundamentally-borked
• http://www.cisco.com/en/US/products/products_security_advisory09186a0080af511d.shtml
• http://www.cisco.com/en/US/products/products_security_response09186a0080a15120.html
• http://www.cpni.gov.uk/Docs/tn-03-09-security-assessment-TCP.pdf
• http://www.mandriva.com/security/advisories?name=MDVSA-2013:150
• http://www.oracle.com/technetwork/topics/security/cpujul2012-392727.html
• http://www.outpost24.com/news/news-2008-10-02.html
• http://www.us-cert.gov/cas/techalerts/TA09-251A.html
• https://docs.microsoft.com/en-us/security-updates/securitybulletins/2009/ms09-048
• https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6340
• https://www.cert.fi/haavoittuvuudet/2008/tcp-vulnerabilities.html

Affected products (2046)

• cpe:2.3:o:bsd:bsd:-:*:*:*:*:*:*:*
• cpe:2.3:o:bsd:bsd:4.1:*:*:*:*:*:*:*
• cpe:2.3:o:bsd:bsd:4.2:*:*:*:*:*:*:*
• cpe:2.3:o:bsd:bsd:4.3:*:*:*:*:*:*:*
• cpe:2.3:o:bsd:bsd:4.4:*:*:*:*:*:*:*
• cpe:2.3:o:bsdi:bsd_os:-:*:*:*:*:*:*:*
• cpe:2.3:o:bsdi:bsd_os:1.1:*:*:*:*:*:*:*
• cpe:2.3:o:bsdi:bsd_os:2.0:*:*:*:*:*:*:*
• cpe:2.3:o:bsdi:bsd_os:2.0.1:*:*:*:*:*:*:*
• cpe:2.3:o:bsdi:bsd_os:2.1:*:*:*:*:*:*:*
• cpe:2.3:o:bsdi:bsd_os:3.0:*:*:*:*:*:*:*
• cpe:2.3:o:bsdi:bsd_os:3.1:*:*:*:*:*:*:*
• cpe:2.3:o:bsdi:bsd_os:3.2:*:*:*:*:*:*:*
• cpe:2.3:o:bsdi:bsd_os:4.0:*:*:*:*:*:*:*
• cpe:2.3:o:bsdi:bsd_os:4.0.1:*:*:*:*:*:*:*
• cpe:2.3:o:bsdi:bsd_os:4.1:*:*:*:*:*:*:*
• cpe:2.3:o:bsdi:bsd_os:4.2:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:-:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:4.1:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:4.1.1:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:4.1.2:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:8.2:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:8.3:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:9.0:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:9.1:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:9.14:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:10.0:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:10.3:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:10.3\(3.3\):*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:10.3\(3.4\):*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:10.3\(4.2\):*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:10.3\(4.3\):*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:10.3\(16\):*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:10.3\(19a\):*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:11:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:11.0:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:11.0\(12\):*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:11.0\(17\):*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:11.0\(17\)bt:*:*:*:*:*:*:*
• cpe:2.3:o:cisco:ios:11.0\(18\):*:*:*:*:*:*:*

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