MEDIUM
CVE-1999-1203
NVD-CWE-OtherPublished: February 12, 1999· Updated: Jun 16, 2026
5.0
CVSS v3.1
Official Description
Multilink PPP for ISDN dialup users in Ascend before 4.6 allows remote attackers to cause a denial of service via a spoofed endpoint identifier.
Technical Analysis
CVE-1999-1203 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.
User Interaction
Scope
Impact
ConfidentialityNone
IntegrityNone
AvailabilityP
AV:N/AC:L/Au:N/C:N/I:N/A:P
Affected Vendors & Products
ascend1 product(s)
multilink ppp for isdn
Source: NVD CPE · 1 total CPE entries
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
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Rapid7 / Metasploit
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PacketStorm
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NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
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All References (6)
Quick Facts
CVE IDCVE-1999-1203
CVSS Score5.0 / 10
SeverityMEDIUM
WeaknessNVD-CWE-Other
CISA KEVNo
Affected1 vendor(s)
PublishedFeb 12, 1999
Related CVEs (NVD-CWE-Other)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-1999-1203 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.