How severe is CVE-1999-1150?

CVE-1999-1150 has a CVSS 2.0 base score of 7.5, rated high severity.

Is CVE-1999-1150 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-1999-1150?

CVE-1999-1150 affects Livingston Portmaster Portmaster. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-1999-1150?

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-1999-1150 published?

CVE-1999-1150 was published on 1998-06-30 and last updated on 2026-06-16.

CVE-1999-1150

CVE-1999-1150 is a high-severity vulnerability in Livingston Portmaster Portmaster with a CVSS 2.0 base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 2.0 base score 7.5)
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Livingston Portmaster Portmaster
Published: 1998-06-30
Last modified: 2026-06-16

Description

Livingston Portmaster routers running ComOS use the same initial sequence number (ISN) for TCP connections, which allows remote attackers to conduct spoofing and hijack TCP sessions.

Frequently asked questions

What is CVE-1999-1150?: Livingston Portmaster routers running ComOS use the same initial sequence number (ISN) for TCP connections, which allows remote attackers to conduct spoofing and hijack TCP sessions.
How severe is CVE-1999-1150?: CVE-1999-1150 has a CVSS 2.0 base score of 7.5, rated high severity.
Is CVE-1999-1150 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-1999-1150?: CVE-1999-1150 affects Livingston Portmaster Portmaster. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-1999-1150?: 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-1999-1150 published?: CVE-1999-1150 was published on 1998-06-30 and last updated on 2026-06-16.

References

Affected products (1)

cpe:2.3:h:livingston_portmaster:portmaster:initial:*:*:*:*:*:*:*

More vulnerabilities in Livingston Portmaster Portmaster

CVE-1999-0218 — Medium (CVSS 5.0): Livingston portmaster machines could be rebooted via a series of commands.

All CVEs affecting Livingston Portmaster Portmaster →