CVE-2006-3551: NCP Secure Enterprise Client (aka VPN/PKI client) 8.30 Build 59, and possibly earlier versions, when the Link

Q: How do I fix CVE-2006-3551?

secure client: upgrade to newer than 8.30_build_59. Exact commands for each OS are on this page.

Q: Is CVE-2006-3551 being exploited?

CVE-2006-3551 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2006-3551 affect?

CVE-2006-3551 affects secure client. Severity is low (CVSS 1.2). NCP Secure Enterprise Client (aka VPN/PKI client) 8.30 Build 59, and possibly earlier versions, when the Link Firewall and Personal Firewall are both configured to block all inbound and outbound network traffic, allows context-dependent att

Q: How urgent is CVE-2006-3551?

Priority 9/100. No elevated risk signals yet.

Routine

LOW 1.2UPGRADE

CVE-2006-3551 is a low-severity flaw (CVSS 1.2) affecting secure client. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

NCP Secure Enterprise Client (aka VPN/PKI client) 8.30 Build 59, and possibly earlier versions, when the Link Firewall and Personal Firewall are both configured to block all inbound and outbound network traffic, allows context-dependent attackers to send inbound UDP traffic with source port 67 and destination port 68, and outbound UDP traffic with source port 68 and destination port 67.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	1.2 (Low)
EPSS exploit chance	0.3% (top 81%)
CISA exploited list	No
Published	2006-07-13
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: ncp network communications

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2006-07-13 00:05 UTCPublished CVE record published
2026-06-16 22:27 UTCUpdated Record last modified

ncp network communications secure client UPGRADE

Affected: <= 8.30_build_59

Fixed in: newer than 8.30_build_59

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy secure-client || rpm -q secure-client || secure-client --version

2. UPGRADE to newer than 8.30_build_59 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade secure-client

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade secure-client

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2006-3551?

secure client: upgrade to newer than 8.30_build_59. Exact commands for each OS are on this page.

Is CVE-2006-3551 being exploited?

CVE-2006-3551 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2006-3551 affect?

CVE-2006-3551 affects secure client. Severity is low (CVSS 1.2). NCP Secure Enterprise Client (aka VPN/PKI client) 8.30 Build 59, and possibly earlier versions, when the Link Firewall and Personal Firewall are both configured to block all inbound and outbound network traffic, allows context-dependent att

How urgent is CVE-2006-3551?

Priority 9/100. No elevated risk signals yet.

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References

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