CVE-2021-32747

CVE-2021-32747 is a medium-severity vulnerability in Icinga with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-200.

Key facts

Description

Icinga Web 2 is an open source monitoring web interface, framework, and command-line interface. A vulnerability in which custom variables are exposed to unauthorized users exists between versions 2.0.0 and 2.8.2. Custom variables are user-defined keys and values on configuration objects in Icinga 2. These are commonly used to reference secrets in other configurations such as check commands to be able to authenticate with a service being checked. Icinga Web 2 displays these custom variables to logged in users with access to said hosts or services. In order to protect the secrets from being visible to anyone, it's possible to setup protection rules and blacklists in a user's role. Protection rules result in `***` being shown instead of the original value, the key will remain. Backlists will hide a custom variable entirely from the user. Besides using the UI, custom variables can also be accessed differently by using an undocumented URL parameter. By adding a parameter to the affected routes, Icinga Web 2 will show these columns additionally in the respective list. This parameter is also respected when exporting to JSON or CSV. Protection rules and blacklists however have no effect in this case. Custom variables are shown as-is in the result. The issue has been fixed in the 2.9.0, 2.8.3, and 2.7.5 releases. As a workaround, one may set up a restriction to hide hosts and services with the custom variable in question.

Frequently asked questions

What is CVE-2021-32747?
Icinga Web 2 is an open source monitoring web interface, framework, and command-line interface. A vulnerability in which custom variables are exposed to unauthorized users exists between versions 2.0.0 and 2.8.2. Custom variables are user-defined keys and values on configuration objects in Icinga 2. These are commonly used to reference secrets in other configurations such as check commands to be able to authenticate with a service being checked. Icinga Web 2 displays these custom variables to logged in users with access to said hosts or services. In order to protect the secrets from being visible to anyone, it's possible to setup protection rules and blacklists in a user's role. Protection rules result in `***` being shown instead of the original value, the key will remain. Backlists will hide a custom variable entirely from the user. Besides using the UI, custom variables can also be accessed differently by using an undocumented URL parameter. By adding a parameter to the affected routes, Icinga Web 2 will show these columns additionally in the respective list. This parameter is also respected when exporting to JSON or CSV. Protection rules and blacklists however have no effect in this case. Custom variables are shown as-is in the result. The issue has been fixed in the 2.9.0, 2.8.3, and 2.7.5 releases. As a workaround, one may set up a restriction to hide hosts and services with the custom variable in question.
How severe is CVE-2021-32747?
CVE-2021-32747 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-32747 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-32747?
CVE-2021-32747 affects Icinga. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-32747?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-32747 published?
CVE-2021-32747 was published on 2021-07-12 and last updated on 2026-06-17.

References

Affected products (1)

More vulnerabilities in Icinga

All CVEs affecting Icinga →

Other CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) vulnerabilities

Browse all CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) vulnerabilities →