CVE-2026-48550: Nagios Core · Cross-site Scripting
Affects Nagios CoreSource CVE Database V5
Not known to be exploited · CVSS 5.1 Medium : upgrade to 4.5.14 when convenient.
Data as of 8 Nov 2026, 23:24 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.5.14
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 12 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.
What to do
Upgrade nagiosenterprises/nagioscore to 4.5.14.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Nagios Enterprises, LLC.Nagios Core | Affected
| Fixed in– |
| Nagios Enterprises, LLC.Nagios XI | Affected
| Fixed in– |
GitHubnagiosenterprises/nagioscorepkg:github/nagiosenterprises/nagioscoreOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, users should exercise caution with links received from untrusted sources and consider restricting access to the Nagios web interface to trusted users only.
Description
Nagios Core before 4.5.14 and Nagios XI before 2026R1.7 are vulnerable to reflected cross-site scripting in cmd.cgi via the NagFormId parameter. An unauthenticated remote attacker can craft a malicious link that, when followed by an authenticated user, executes arbitrary JavaScript in the victim's browser.