CVE-2021-22143: Elastic APM .NET Agent information disclosure

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-11-22 · updated 2026-06-17
Weakness: CWE-200

Description

The Elastic APM .NET Agent can leak sensitive HTTP header information when logging the details during an application error. Normally, the APM agent will sanitize sensitive HTTP header details before sending the information to the APM server. During an application error it is possible the headers will not be sanitized before being sent.

Affected products

Elastic APM .NET Agent: before 1.10.0 — fixed in 1.10.0

How to fix

Upgrade to a fixed version: Elastic APM .NET Agent 1.10.0. Check the vendor advisory for mitigations.

References

https://discuss.elastic.co/t/elastic-apm-net-agent-1-10-0-security-update/274668
https://www.elastic.co/community/security
https://discuss.elastic.co/t/elastic-apm-net-agent-1-10-0-security-update/274668
https://www.elastic.co/community/security

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