What is CVE-1999-1157?

CVE-1999-1157 is a vulnerability in Microsoft Windows Nt. Published 1999-12-31.

Is CVE-1999-1157 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Microsoft Windows Nt

CVE-1999-1157

Tcpip.sys in Windows NT 4.0 before SP4 allows remote attackers to cause a denial of service via an ICMP Subnet Mask Address Request packet, when certain multiple IP addresses are bound to the same network interface.

Published 1999-12-31 · last modified 2026-06-16.

CVSS v2 metric

CVSS v2 base score 5.0 (Medium). Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P. This CVE predates CVSS v3 and has no v3 score from NVD.

EPSS exploit prediction

EPSS: 0.133 (96.3th percentile), scored 2026-09-28.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 96th percentile — 96.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.133 · newest: 0.133 · change: 0.000

Affected products

Microsoft Windows Nt

Public proof-of-concept exploits

ARPSyndicate/cve-scores

References

exchange.xforce.ibmcloud.com/vulnerabilities/3894 (vdb-entry)
support.microsoft.com/support/kb/articles/Q192/7/74.ASP (vendor-advisory, Patch, Vendor Advisory)

Frequently asked questions

What is CVE-1999-1157?: CVE-1999-1157 is a vulnerability in Microsoft Windows Nt. Published 1999-12-31.
Is CVE-1999-1157 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.