CVE-1999-0820

FreeBSD seyon - Privilege Escalation

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-1999-0820. PoCs published by Shawn Hillis.

AI-analyzed exploit summary This exploit leverages a relative pathname vulnerability in Seyon to spawn a shell with elevated privileges (setgid dialer on FreeBSD or root on Irix). The attacker compiles a malicious program named 'seyon-emu' and manipulates the PATH to execute it instead of the legitimate Seyon binary.

Description

FreeBSD seyon allows users to gain privileges via a modified PATH variable for finding the xterm and seyon-emu commands.

Exploits (1)

exploitdb WORKING POC VERIFIED
by Shawn Hillis · textlocalfreebsd
https://www.exploit-db.com/exploits/19609

This exploit leverages a relative pathname vulnerability in Seyon to spawn a shell with elevated privileges (setgid dialer on FreeBSD or root on Irix). The attacker compiles a malicious program named 'seyon-emu' and manipulates the PATH to execute it instead of the legitimate Seyon binary.

Classification
Working Poc 95%
Attack Type
Lpe
Complexity
Trivial
Reliability
Reliable
Target: Seyon (version not specified)
No auth needed
Prerequisites: Access to a system with Seyon installed · Ability to compile and execute a binary · Write permissions in a directory included in PATH
mistral-large-3 · analyzed Feb 16, 2026 Full analysis →

References (2)

Core 2
Core References
Third Party Advisory, VDB Entry vdb-entry x_refsource_bid
http://www.securityfocus.com/bid/838
Third Party Advisory, VDB Entry vdb-entry x_refsource_osvdb
http://www.osvdb.org/5996

Scores

EPSS 0.0067
EPSS Percentile 47.8%

Details

Status published
Products (1)
freebsd/freebsd 3.3
Published Dec 01, 1999
Tracked Since Feb 18, 2026