CVE-1999-0063

Cisco IOS - Denial of Service via Malicious UDP Syslog Packets

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-1999-0063. PoCs published by Olaf Selke.

AI-analyzed exploit summary This is a writeup describing a DoS vulnerability in Cisco IOS devices via UDP port 514 (syslog). It includes a list of vulnerable devices and a simple nmap command to test for the vulnerability.

Description

Cisco IOS 12.0 and other versions can be crashed by malicious UDP packets to the syslog port.

Exploits (1)

exploitdb WRITEUP VERIFIED
by Olaf Selke · textdoshardware
https://www.exploit-db.com/exploits/19531

This is a writeup describing a DoS vulnerability in Cisco IOS devices via UDP port 514 (syslog). It includes a list of vulnerable devices and a simple nmap command to test for the vulnerability.

Classification
Writeup 90%
Attack Type
Dos
Complexity
Trivial
Reliability
Theoretical
Target: Cisco IOS (various versions and devices)
No auth needed
Prerequisites: Network access to UDP port 514 on the target device
mistral-large-3 · analyzed Feb 16, 2026 Full analysis →

References (1)

Core 1
Core References
Third Party Advisory, VDB Entry x_refsource_misc
https://exchange.xforce.ibmcloud.com/vulnerabilities/CVE-1999-0063

Scores

EPSS 0.0825
EPSS Percentile 94.2%

Details

Status published
Products (12)
cisco/ios 11.3aa
cisco/ios 11.3db
cisco/ios 12.0
cisco/ios 12.0\(1\)w
cisco/ios 12.0\(1\)xa3
cisco/ios 12.0\(1\)xb
cisco/ios 12.0\(1\)xe
cisco/ios 12.0\(2\)xc
cisco/ios 12.0\(2\)xd
cisco/ios 12.0db
... and 2 more
Published Jan 11, 1999
Tracked Since Feb 18, 2026