CVE intelligence and bounded remediation
CVE-2021-40344 — An issue was discovered in Nagios XI 5.8.5
High
CVSS 7.2
An issue was discovered in Nagios XI 5.8.5. In the Custom Includes section of the Admin panel, an administrator can upload files with arbitrary extensions as long as the MIME type corresponds to an image. Therefore it is possible to upload a crafted PHP script to achieve remote command execution.
- Severity
- High
- CVSS
- 7.2 (3.1)
- Published
- 2021-10-26
- CISA KEV
- Not currently listed
- Ecosystem
- software/application
- Weaknesses
- CWE-434
Affected products
- nagios / nagios_xi / 5.8.5
Matched remediation archetype
Path traversal, unsafe upload, and file handling
This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.
Check exposure
- Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
- Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
- Review canonicalization and containment checks across supported operating systems and storage backends.
Remediate safely
- Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
- Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
- Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.
Authoritative sources
Complete CVE record and remediation plan
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