CVE-2021-40344
An issue was discovered in Nagios XI 5.8.5. In the Custom Includes section of the Admin panel, an...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2021-40344- CVSS 3.1
- 7.2 High
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 6.5 Medium
AV:N/AC:L/Au:S/C:P/I:P/A:P - Weakness
- CWE-434
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2021-40344- Updated
- 2026-11-02
EUVDEUVD-2021-27523 No score
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.
- Record
EUVD-2021-27523- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-r8gx-p4rw-3vpj No score
An issue was discovered in Nagios XI 5.8.5. In the Custom Includes section of the Admin panel, an...
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.
- Record
GHSA-r8gx-p4rw-3vpj- Weakness
- CWE-434
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-40344 is a high vulnerability (CVSS 7.2) in Nagios Xi, published October 26, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 64.8%, the 99th percentile. No source names a fixed version.