How severe is CVE-2006-4436?

CVE-2006-4436 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-2006-4436 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2006-4436?

CVE-2006-4436 primarily affects Openbsd. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2006-4436?

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

When was CVE-2006-4436 published?

CVE-2006-4436 was published on 2006-08-29 and last updated on 2026-06-16.

CVE-2006-4436

CVE-2006-4436 is a medium-severity vulnerability in Openbsd with a CVSS 2.0 base score of 5.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 2.0 base score 5.0)
EPSS exploit prediction: 2% (75th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Openbsd
Published: 2006-08-29
Last modified: 2026-06-16

Description

isakmpd in OpenBSD 3.8, 3.9, and possibly earlier versions, creates Security Associations (SA) with a replay window of size 0 when isakmpd acts as a responder during SA negotiation, which allows remote attackers to replay IPSec packets and bypass the replay protection.

Frequently asked questions

What is CVE-2006-4436?: isakmpd in OpenBSD 3.8, 3.9, and possibly earlier versions, creates Security Associations (SA) with a replay window of size 0 when isakmpd acts as a responder during SA negotiation, which allows remote attackers to replay IPSec packets and bypass the replay protection.
How severe is CVE-2006-4436?: CVE-2006-4436 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-2006-4436 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2006-4436?: CVE-2006-4436 primarily affects Openbsd. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2006-4436?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2006-4436 published?: CVE-2006-4436 was published on 2006-08-29 and last updated on 2026-06-16.

References

Affected products (2)

cpe:2.3:o:openbsd:openbsd:3.8:*:*:*:*:*:*:*
cpe:2.3:o:openbsd:openbsd:3.9:*:*:*:*:*:*:*

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