CVE-2026-41484: OpenTelemetry.Exporter.OneCollector vulnerable to denial of service via unbounded HTTP error response body
Summary
When exporting telemetry to a back-end/collector over HTTP using the OpenTelemetry.Exporter.OneCollector exporter, if the request results in a unsuccessful request (i.e. HTTP 4xx or 5xx), the response is read into memory with no upper-bound on the number of bytes consumed.
This could cause memory exhaustion in the consuming application if the configured back-end/collector endpoint is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned by the response.
Details
The HttpJsonPostTransport class reads the response body when a non-200 HTTP status code is received when exporting telemetry to aid debugging by operators so that the error response is included in the logs emitted by the exporter.
An attacker who controls the configured endpoint, or who can intercept traffic to them (MiTM), can return an arbitrarily large response body. This causes unbounded heap allocation in the consuming process, leading to high transient memory pressure, garbage-collection stalls, or an OutOfMemoryException that terminates the process.
Impact
If an application using the OneCollector exporter is configured to use a back-end/collector endpoint that is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned by the response the application could have its memory exhausted and create a denial-of-service condition.
Mitigation
The application's configured back-end/collector endpoint needs to behave maliciously. If the collector/back-end is a well-behaved implementation response bodies should not be excessively large if a request error occurs.
Workarounds
Use network-level controls (firewall rules, mTLS, service mesh) to prevent Man-in-the-Middle (MitM) attacks on the configured back-end/collector endpoint.
Remediation
#4117 updates the OneCollector exporter to limit the number of bytes read from the response body in an error condition to 4MiB.
Resources
- #4117
Other sources
OpenTelemetry.Exporter.OneCollector is a .NET exporter that sends telemetry to a OneCollector back-end over HTTP. In versions 1.15.0 and earlier, when a request to the configured back-end or collector results in an unsuccessful HTTP 4xx or 5xx response, the HttpJsonPostTransport class reads the entire response body into memory with no upper bound on the number of bytes consumed in order to include the error response in operator logs.
An attacker who controls the configured endpoint, or who can intercept traffic to it via a man-in-the-middle attack, can return an arbitrarily large response body. This causes unbounded heap allocation in the consuming process, leading to high transient memory pressure, garbage-collection stalls, or an OutOfMemoryException that terminates the process. As a workaround, use network-level controls such as firewall rules, mTLS, or a service mesh to prevent man-in-the-middle attacks on the configured back-end or collector endpoint. This issue is fixed in version 1.15.1, which limits the number of bytes read from the response body in an error condition to 4 MiB.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-41484?
CVE-2026-41484 is considered a medium severity vulnerability due to its potential for resource exhaustion.
How do I fix CVE-2026-41484?
To fix CVE-2026-41484, upgrade the OpenTelemetry.Exporter.OneCollector package to version 1.15.1 or higher.
What is affected by CVE-2026-41484?
CVE-2026-41484 affects versions of the OpenTelemetry.Exporter.OneCollector package up to and including 1.15.0.
What type of vulnerability is CVE-2026-41484?
CVE-2026-41484 is a denial of service vulnerability due to unbounded memory consumption when handling HTTP responses.
Can CVE-2026-41484 cause data loss?
CVE-2026-41484 can lead to application crashes or slowdowns but does not directly cause data loss.