[NEW] [high] Nagios Core and Nagios XI: Multiple vulnerabilities

highCVE-2026-48550 CVE-2026-48551 CVE-2026-48552 CVE-2026-48553 CVE-2026-48554

An attacker can exploit multiple vulnerabilities in Nagios Core and Nagios Enterprises Nagios XI to conduct Cross-Site Scripting attacks, execute arbitrary code, bypass security measures and manipulate data.

CSIRTS triage

Cross-site scripting Remote code execution Authentication bypass Code injection

What: Multiple vulnerabilities in Nagios Core and Nagios XI enable attackers to conduct cross-site scripting attacks, execute arbitrary code, bypass security measures, and manipulate data.
Who is affected: Nagios Core and Nagios XI deployments of unspecified versions are affected.
Urgency: High urgency; code execution and XSS capabilities pose significant risk to monitoring infrastructure.
Action: Update both Nagios Core and Nagios XI to patched versions addressing CVE-2026-48550 through CVE-2026-48554.

AI-assisted analysis generated from the source advisory — verify against the original.

Details

Source: CERT-Bund (BSI) Security Advisories (DE · national-cert · site)
Severity: high
Published: 2026-08-13
Exploitation: Not in CISA KEV at last sync
Language: Machine-translated to English — verify against the original

Original advisory: https://wid.cert-bund.de/portal/wid/securityadvisory?name=WID-SEC-2026-2819

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-485500.27% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 18% of all EPSS-scored CVEs.
Low exploitation riskCVE-2026-485510.17% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 7% of all EPSS-scored CVEs.
Low exploitation riskCVE-2026-485520.17% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 6% of all EPSS-scored CVEs.
Low exploitation riskCVE-2026-485530.52% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 43% of all EPSS-scored CVEs.
Low exploitation riskCVE-2026-485540.52% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 43% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-48550	coverage & exploitation status	NVD · CVE.org
CVE-2026-48551	coverage & exploitation status	NVD · CVE.org
CVE-2026-48552	coverage & exploitation status	NVD · CVE.org
CVE-2026-48553	coverage & exploitation status	NVD · CVE.org
CVE-2026-48554	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for Nagios Core and

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

mediumCVE-2026-48549: Nagios Core before 4.5.13 and Nagios XI before 2026R1.5 contains a CSRF vulnerability in cmd.c…nvd · 2026-08-26
mediumCVE-2026-48548: Nagios Core before 4.5.12 contains a cross-site request forgery vulnerability in cmd.cgi where…nvd · 2026-08-26
highCVE-2026-48554: Nagios Core before 4.5.14 and Nagios XI before 2026R1.7 are vulnerable to authenticated remote…nvd · 2026-08-12
highCVE-2026-48553: Nagios Core before 4.5.13 and Nagios XI before 2026R1.5 are vulnerable to authenticated remote…nvd · 2026-08-12
mediumCVE-2026-48552: Nagios Core before 4.5.14 and Nagios XI before 2026R1.7 are vulnerable to DOM-based cross-site…nvd · 2026-08-12
highCVE-2026-48551: Nagios Core before 4.5.14 and Nagios XI before 2026R1.7 contain a cross-site request forgery p…nvd · 2026-08-12