7.5

CVE-2021-37698: debian debian_linux Improper Certificate Validation

CVSS: 7.5v3.1HighModified
AliasesUBUNTU-CVE-2021-37698DEBIAN-CVE-2021-37698
Published 19-08-2021Last modified 03-11-2025
Open JSON

Vulnerability summary

CVE-2021-37698 is a high (CVSS 7.5) Improper Certificate Validation vulnerability in debian debian_linux. EPSS estimates a 1.38% chance of exploitation in the next 30 days, higher than 71.7% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
1.38%
0%100%
Low · -0.04 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 4 · Related 2
DLA-2816-1DLA-3953-1OPENSUSE-SU-2024:10856-1SUSE-SU-2022:3725-1

Timeline

  1. 19-08-2021
    PublishedVulnerability first disclosed.
  2. 03-11-2025
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

5 scores · 4 sources · 2 versions

EPSS trend

Probability

1.38%

Chance of exploitation in the next 30 days

Percentile

72%

Versus all other CVEs

30-day change

-0.04 pp

From 1.42% on 20-09-2026

20-09-202620-10-2026
EPSS score
1.38%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Debian2 products
Icinga2 products
  • icinga≥ 2.5.0, < 2.11.10 | ≥ 2.12.0, < 2.12.6 | ≥ 2.13.0, < 2.13.1
  • icinga2≥ 2.5.0, ≤ 2.13.0
Ubuntu1 product
  • icinga2All versions (No fix recorded)

3 vendors · 5 products

References

10 links