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CVE-2021-37698

Missing TLS service certificate validation in GelfWriter, ElasticsearchWriter, InfluxdbWriter and Influxdb2Writer

7.5 HighFix available

CVE-2021-37698 is a high vulnerability (CVSS 7.5) in Icinga, published August 19, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.38%, the 72nd percentile. Fixed in icinga2 2.12.6-r0.

Icinga is a monitoring system which checks the availability of network resources, notifies users of outages, and generates performance data for reporting. In versions 2.5.0 through 2.13.0, ElasticsearchWriter, GelfWriter, InfluxdbWriter and Influxdb2Writer do not verify the server's certificate despite a certificate authority being specified. Icinga 2 instances which connect to any of the mentioned time series databases (TSDBs) using TLS over a spoofable infrastructure should immediately upgrade to version 2.13.1, 2.12.6, or 2.11.11 to patch the issue. Such instances should also change the credentials (if any) used by the TSDB writer feature to authenticate against the TSDB. There are no workarounds aside from upgrading.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
None
Availability
None

Exploit likelihood

1.38%Up 0.3 points since Aug 20, 2021
90%50%10%1%

What each source reports

CVE List Score used 7.5

Missing TLS service certificate validation in GelfWriter, ElasticsearchWriter, InfluxdbWriter and Influxdb2Writer

Icinga is a monitoring system which checks the availability of network resources, notifies users of outages, and generates performance data for reporting. In versions 2.5.0 through 2.13.0, ElasticsearchWriter, GelfWriter, InfluxdbWriter and Influxdb2Writer do not verify the server's certificate despite a certificate authority being specified. Icinga 2 instances which connect to any of the mentioned time series databases (TSDBs) using TLS over a spoofable infrastructure should immediately upgrade to version 2.13.1, 2.12.6, or 2.11.11 to patch the issue. Such instances should also change the credentials (if any) used by the TSDB writer feature to authenticate against the TSDB. There are no workarounds aside from upgrading.

Record
CVE-2021-37698
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness
CWE-295
Updated
2026-11-02
EUVDEUVD-2021-24193 7.5

Icinga is a monitoring system which checks the availability of network resources, notifies users of outages, and generates performance data for reporting. In versions 2.5.0 through 2.13.0, ElasticsearchWriter, GelfWriter, InfluxdbWriter and Influxdb2Writer do not verify the server's certificate despite a certificate authority being specified. Icinga 2 instances which connect to any of the mentioned time series databases (TSDBs) using TLS over a spoofable infrastructure should immediately upgrade to version 2.13.1, 2.12.6, or 2.11.11 to patch the issue. Such instances should also change the credentials (if any) used by the TSDB writer feature to authenticate against the TSDB. There are no workarounds aside from upgrading.

Record
EUVD-2021-24193
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated
2026-11-02
NVD 7.5

Icinga is a monitoring system which checks the availability of network resources, notifies users of outages, and generates performance data for reporting. In versions 2.5.0 through 2.13.0, ElasticsearchWriter, GelfWriter, InfluxdbWriter and Influxdb2Writer do not verify the server's certificate despite a certificate authority being specified. Icinga 2 instances which connect to any of the mentioned time series databases (TSDBs) using TLS over a spoofable infrastructure should immediately upgrade to version 2.13.1, 2.12.6, or 2.11.11 to patch the issue. Such instances should also change the credentials (if any) used by the TSDB writer feature to authenticate against the TSDB. There are no workarounds aside from upgrading.

Record
CVE-2021-37698
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS 2.0
5.0 MediumAV:N/AC:L/Au:N/C:P/I:N/A:N
Weakness
CWE-295
Updated
2026-11-02
OSVALPINE-CVE-2021-37698 7.5

Icinga is a monitoring system which checks the availability of network resources, notifies users of outages, and generates performance data for reporting. In versions 2.5.0 through 2.13.0, ElasticsearchWriter, GelfWriter, InfluxdbWriter and Influxdb2Writer do not verify the server's certificate despite a certificate authority being specified. Icinga 2 instances which connect to any of the mentioned time series databases (TSDBs) using TLS over a spoofable infrastructure should immediately upgrade to version 2.13.1, 2.12.6, or 2.11.11 to patch the issue. Such instances should also change the credentials (if any) used by the TSDB writer feature to authenticate against the TSDB. There are no workarounds aside from upgrading.

Record
ALPINE-CVE-2021-37698
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated
2026-11-03
OSV 7.5

Icinga is a monitoring system which checks the availability of network resources, notifies users of outages, and generates performance data for reporting. In versions 2.5.0 through 2.13.0, ElasticsearchWriter, GelfWriter, InfluxdbWriter and Influxdb2Writer do not verify the server's certificate despite a certificate authority being specified. Icinga 2 instances which connect to any of the mentioned time series databases (TSDBs) using TLS over a spoofable infrastructure should immediately upgrade to version 2.13.1, 2.12.6, or 2.11.11 to patch the issue. Such instances should also change the credentials (if any) used by the TSDB writer feature to authenticate against the TSDB. There are no workarounds aside from upgrading.

Record
CVE-2021-37698
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated
2026-11-02
OSVDEBIAN-CVE-2021-37698 7.5

Icinga is a monitoring system which checks the availability of network resources, notifies users of outages, and generates performance data for reporting. In versions 2.5.0 through 2.13.0, ElasticsearchWriter, GelfWriter, InfluxdbWriter and Influxdb2Writer do not verify the server's certificate despite a certificate authority being specified. Icinga 2 instances which connect to any of the mentioned time series databases (TSDBs) using TLS over a spoofable infrastructure should immediately upgrade to version 2.13.1, 2.12.6, or 2.11.11 to patch the issue. Such instances should also change the credentials (if any) used by the TSDB writer feature to authenticate against the TSDB. There are no workarounds aside from upgrading.

Record
DEBIAN-CVE-2021-37698
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated
2026-11-02
OSVUBUNTU-CVE-2021-37698 7.5

Icinga is a monitoring system which checks the availability of network resources, notifies users of outages, and generates performance data for reporting. In versions 2.5.0 through 2.13.0, ElasticsearchWriter, GelfWriter, InfluxdbWriter and Influxdb2Writer do not verify the server's certificate despite a certificate authority being specified. Icinga 2 instances which connect to any of the mentioned time series databases (TSDBs) using TLS over a spoofable infrastructure should immediately upgrade to version 2.13.1, 2.12.6, or 2.11.11 to patch the issue. Such instances should also change the credentials (if any) used by the TSDB writer feature to authenticate against the TSDB. There are no workarounds aside from upgrading.

Record
UBUNTU-CVE-2021-37698
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated
2026-11-02
OSVopenSUSE-SU-2024:10856-1 No score

icinga2-2.13.1-1.3 on GA media

These are all security issues fixed in the icinga2-2.13.1-1.3 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2024:10856-1
Updated
2026-11-02
OSVSUSE-SU-2022:3725-1 No score

Security update for icinga2

This update for icinga2 fixes the following issues:

  • CVE-2020-14004: prepare-dirs script allows for symlink attack in the icinga user context. (bsc#1172171)
  • CVE-2020-29663: ignoring CRL, where revoked certificates due for renewal will automatically be renewed. (bsc#281137)
  • CVE-2021-37698: Missing TLS server certificate validation in ElasticsearchWriter, GelfWriter, InfluxdbWriter and Influxdb2Writer. (bsc#281137)
Record
SUSE-SU-2022:3725-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
icinga2
Alpine:v3.14
before 2.12.6-r0
2.12.6-r0
icinga2
Alpine:v3.15
before 2.13.1-r0
2.13.1-r0
icinga2
Alpine:v3.16
before 2.13.1-r0
2.13.1-r0
icinga2
Alpine:v3.17
before 2.13.1-r0
2.13.1-r0
icinga2
Alpine:v3.18
before 2.13.1-r0
2.13.1-r0
icinga2
Alpine:v3.19
before 2.13.1-r0
2.13.1-r0
icinga2
Alpine:v3.20
before 2.13.1-r0
2.13.1-r0
icinga2
Alpine:v3.21
before 2.13.1-r0
2.13.1-r0
icinga2
Alpine:v3.22
before 2.13.1-r0
2.13.1-r0
icinga2
Alpine:v3.23
before 2.13.1-r0
2.13.1-r0
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Affected packages
PackageAffectedFixed
icinga2
Alpine:v3.24
before 2.13.1-r0
2.13.1-r0
icinga2
Debian:12
before 2.13.1-1
2.13.1-1
icinga2
Debian:13
before 2.13.1-1
2.13.1-1
icinga2
Debian:14
before 2.13.1-1
2.13.1-1
icinga2
Debian:9
before 2.6.0-2+deb9u2, plus listed versions
2.6.0-22.6.0-2+deb9u1
2.6.0-2+deb9u2
icinga2
Debian:11
before 2.12.3-1+deb11u1, plus listed versions
2.12.3-1
2.12.3-1+deb11u1
icinga2
SUSE:Linux Enterprise Module for HPC 12
before 2.8.2-3.6.1
2.8.2-3.6.1
icinga2
Ubuntu:16.04:LTS
All versions, plus listed versions
2.3.8-1build12.3.11-12.4.0-12.4.1-12.4.1-22.4.1-2ubuntu1
None known
icinga2
Ubuntu:18.04:LTS
All versions, plus listed versions
2.7.0-12.8.1-0ubuntu2
None known
icinga2
Ubuntu:20.04:LTS
All versions, plus listed versions
2.10.5-1build12.11.2-12.11.2-1ubuntu12.11.2-1ubuntu22.11.2-1ubuntu3
None known
icinga2
Ubuntu:22.04:LTS
All versions, plus listed versions
2.12.3-12.13.1-12.13.2-12.13.2-1build12.13.2-1build2
None known
icinga2
openSUSE:Tumbleweed
before 2.13.1-1.3
2.13.1-1.3

History

History
WhenChangedSources
2026-11-03affected, aliases, referencesOSV
2026-11-02createdCVE List, EUVD, NVD, OSV

References

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