Description
qh_core in Nagios Core 4.4.1 and earlier is prone to a NULL pointer dereference vulnerability, which allows attackers to cause a local denial-of-service condition by sending a crafted payload to the listening UNIX socket.
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 | nagios4 | 4.3.4-3 | — |
| Debian 13 | nagios4 | 4.3.4-3 | — |
| Debian 12 | nagios4 | 4.3.4-3 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Package Hub 15 SP1 | nagios | 4.4.5-bp151.4.3.1 | openSUSE-SU-2020:0517-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.1 | nagios | 4.4.5-lp151.5.4.1 | openSUSE-SU-2020:0500-1 |
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.
Exploit-DB 1
- Nagios Core 4.4.1 - Denial of Service EDB-45082 · dos · Jul 24, 2018
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 2
- openSUSE-SU-2020:0500-1 Security update for nagios SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:0517-1 Security update for nagios SUSE / openSUSE Security Updates · May 7, 2025