CVE-2021-40344 in the critical feed json
An issue was discovered in Nagios XI 5.8.5.
published 2021-10-26 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-27523
- cvss
- 7.2
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 64.8%
- EPSS 64.8% chance of exploitation in 30 days, percentile 99.2%
- public exploits
- 0
- none known
Summary
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.
Exploit prediction
64.80% chance of exploitation in the next 30 days, higher than 99.2% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- synacktiv.com https://www.synacktiv.com/sites/default/files/2021-10/Nagios_XI_multiple_vulnerabilities_0.pdf referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 7.2 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 6.5 | AV:N/AC:L/Au:S/C:P/I:P/A:P |
Classification
- Weakness
-
- CWE-434 Unrestricted Upload of File with Dangerous Type
References
-
synacktiv.com
/sites/default/files/2021-10/Nagios_XI_multiple_vulnerabilities_0.pdf
exploit, third-party-advisory
-
assets.nagios.com
/downloads/nagiosxi/CHANGES-5.TXT
release-notes, vendor-advisory
-
synacktiv.com
not-applicable
Sources
- CVE List CVE-2021-40344
- NVD CVE-2021-40344
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.