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PatchSiren cyber security CVE debrief

CVE-2019-15949 Nagios CVE debrief

CVE-2019-15949 is a Nagios XI remote code execution vulnerability that CISA has listed in the Known Exploited Vulnerabilities catalog. Because it is marked as known exploited, defenders should treat unpatched Nagios XI deployments as a high-priority remediation item and apply vendor updates as soon as possible.

Vendor
Nagios
Product
Nagios XI
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2021-11-03
Original CVE updated
2021-11-03
Advisory published
2021-11-03
Advisory updated
2021-11-03

Who should care

Security teams, system administrators, and MSPs responsible for Nagios XI deployments—especially instances that are internet-facing or used for centralized monitoring—should prioritize this CVE.

Technical summary

The supplied corpus identifies CVE-2019-15949 as a Nagios XI remote code execution vulnerability and confirms its inclusion in CISA’s KEV catalog. The available sources do not provide affected-version ranges, root cause details, or exploit prerequisites, so the safest defensive assumption is that vulnerable, unpatched Nagios XI installations may be subject to attacker-controlled code execution. Use the official vendor guidance and CISA KEV entry to drive remediation and exposure review.

Defensive priority

High. CISA has classified this CVE as known exploited, which makes remediation urgent for any affected Nagios XI instance.

Recommended defensive actions

  • Inventory all Nagios XI deployments and determine which instances are exposed to users or the internet.
  • Check the installed Nagios XI version against official vendor guidance and update immediately to a fixed release.
  • Follow CISA’s required action: apply updates per vendor instructions.
  • Restrict administrative access to Nagios XI interfaces and review network exposure until patching is complete.
  • Monitor authentication, configuration, and application logs for unusual activity around Nagios XI hosts.
  • After remediation, confirm the fix by rechecking versions and validating that no unpatched instances remain.

Evidence notes

This debrief is based only on the supplied corpus and official links. The CISA KEV source explicitly lists CVE-2019-15949 as a Nagios XI remote code execution vulnerability and notes the required action to apply updates per vendor instructions. The CVE.org and NVD links are included as canonical record and vulnerability-database references, but no further technical details were supplied here, so no unsupported exploitation or version claims are included.

Official resources

The supplied record is dated 2021-11-03 for both the CVE metadata and the CISA KEV entry. This debrief uses that supplied publication context and does not infer an earlier issue date beyond the CVE identifier itself.