RCE in Nagios Enterprises, Llc Xi
CVE-2026-119742
Nagios XI before 2026R2 contains an OS command injection vulnerability in the MIB upload feature where the install_mib() function in mibs.php sanitizes uploaded filenames with an incomplete character-substitution filter that omits semicolons, pipes, and non-space IFS whitespace characters before passing them to a grep command run via exec(). An authenticated administrator can upload a MIB file with a crafted filename using tab characters to bypass the deny-list and pipe to sh via a multipart POST request to mibs.php, resulting in arbitrary OS command execution as the web server user.
Vulnerability class: Command Injection (OS Command Injection)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- www.nagios.com/security-disclosures/nagios-xi/2026r2/ (release-notes, patch)
- www.vulncheck.com/advisories/nagios-xi-2026r2-os-command-injection-via-mibs-php (third-party-advisory)
Frequently asked questions
- What is CVE-2026-119742?
- CVE-2026-119742 is a high-severity vulnerability in Nagios Enterprises, Llc Xi, classified under OS Command Injection. CVSS score: 7.2/10. Published 2026-11-03.
- How severe is CVE-2026-119742?
- High severity. CVSS v3 base score is 7.2 out of 10.