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CVE-2004-2621: Contivity VPN Client can be hijacked by attackers

CVE-2004-2621 · published 21 years ago

Summary

The Contivity VPN Client versions 2.1.7, 3.00, 3.01, 4.91 and 5.01 may let an attacker intercept your connection because it checks the server’s certificate too late. This timing gap can let a malicious party pose as the VPN gateway and read or alter traffic. Update to a newer version or apply the vendor’s recommended fix to ensure the certificate is validated before any connection is established.

What to do

The CVE record does not list a fixed version. Check the vendor's site or the advisory links below - a fix may already be released.

Affected software

Vendor	Product	Affected versions
nortel	contivity	2.1.7 3.00 3.01 4.91 5.01 `cpe:2.3:h:nortel:contivity:2.1.7:::::::*`

Original advisory text

Nortel Contivity VPN Client 2.1.7, 3.00, 3.01, 4.91, and 5.01, when opening a VPN tunnel, does not check the gateway certificate until after a dialog box has been displayed to the user, which creates a race condition that allows remote attackers to perform a man-in-the-middle (MITM) attack.

References

Fix within

Internet-facing 60 days

Internal At next upgrade

Not known to be exploited
Needs hands-on effort to exploit (estimated)
Gives an attacker partial control (estimated)

Severity

4.0 Medium

Exploitation

<1% chance of attack within 30 days

Timeline

Published31 Dec 2004

Updated4 Nov 2026

First seen29 Sep 2026

Sources

CVE-2004-2621 · NVD

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