Description
xymond in Xymon 4.1.x, 4.2.x, and 4.3.x before 4.3.25 allow remote authenticated users to execute arbitrary commands via shell metacharacters in the adduser_name argument in (1) web/useradm.c or (2) web/chpasswd.c.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | xymon | 4.3.25-1 | — |
| Debian 13 | xymon | 4.3.25-1 | — |
| Debian 12 | xymon | 4.3.25-1 | — |
| Debian 8 | xymon | 4.3.17-6+deb8u1 | DSA-3495-1 |
| Debian 7 | xymon | 4.3.0~beta2.dfsg-9.1+deb7u1 | DLA-488-1 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Metasploit 1 module
-
Xymon useradm Command Execution
exploit/unix/webapp/xymon_useradm_cmd_exec
Exploit-DB 1
- Xymon 4.3.25 - useradm Command Execution (Metasploit) EDB-47114 · remote · Jul 12, 2019 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 2
- DLA-488-1 xymon - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-3495-1 xymon - security update Debian Security (DSA / DLA) · Mar 9, 2026
References
- 20160214 Xymon: Critical security issues in all versions prior to 4.3.25 mailing-list
- https://sourceforge.net/p/xymon/code/7892/
- DSA-3495 vendor-advisory
- http://packetstormsecurity.com/files/135758/Xymon-4.3.x-Buffer-Overflow-Code-Execution-Information-Disclosure.html
- http://packetstormsecurity.com/files/153620/Xymon-useradm-Command-Execution.html