CVE-2023-45142 OpenTelemetry-Go Contrib has DoS vulnerability in otelhttp due to unbound cardinality metrics

What is CVE-2023-45142?

CVE-2023-45142 is a high-severity denial of service vulnerability in open-telemetry opentelemetry-go-contrib, published on 12 Oct 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

OpenTelemetry-Go Contrib is a collection of third-party packages for OpenTelemetry-Go. A handler wrapper out of the box adds labels `http.user_agent` and `http.method` that have unbound cardinality. It leads to the server's potential memory exhaustion when many malicious requests are sent to it. HTTP header User-Agent or HTTP method for requests can be easily set by an attacker to be random and long. The library internally uses `httpconv.ServerRequest` that records every value for HTTP `method` and `User-Agent`. In order to be affected, a program has to use the `otelhttp.NewHandler` wrapper and not filter any unknown HTTP methods or User agents on the level of CDN, LB, previous middleware, etc. Version 0.44.0 fixed this issue when the values collected for attribute `http.request.method` were changed to be restricted to a set of well-known values and other high cardinality attributes were removed. As a workaround to stop being affected, `otelhttp.WithFilter()` can be used, but it requires manual careful configuration to not log certain requests entirely. For convenience and safe usage of this library, it should by default mark with the label `unknown` non-standard HTTP methods and User agents to show that such requests were made but do not increase cardinality. In case someone wants to stay with the current behavior, library API should allow to enable it.

Weakness: CWE-770

Which versions are affected by CVE-2023-45142?

21 open source packages ship an affected version, including go.opentelemetry.io/contrib/instrumentation/github.com/emicklei/go-restful/otelrestful, go.opentelemetry.io/contrib/instrumentation/github.com/gin-gonic/gin/otelgin and go.opentelemetry.io/contrib/instrumentation/github.com/gorilla/mux/otelmux. It affects 1 product.

Products include Opentelemetry Opentelemetry.

How do I fix CVE-2023-45142?

Upgrade go.opentelemetry.io/contrib/instrumentation/github.com/emicklei/go-restful/otelrestful to 0.44.0 or later.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2023-45142 being exploited?

There is no known exploitation of CVE-2023-45142 in the wild and no public exploit code.

Other vulnerabilities in open-telemetry opentelemetry-go-contrib

• CVE-2026-29181 OpenTelemetry-Go multi-value `baggage` header extraction causes excessive allocations (remote dos amplification) High 7.5
• CVE-2023-47108 DoS vulnerability in otelgrpc (uncontrolled resource consumption) due to unbound cardinality metrics High 7.5
• CVE-2023-43810 opentelemetry-instrumentation Denial of Service vulnerability due to unbound cardinality metrics High 7.5
• CVE-2026-39883 opentelemetry-go: BSD kenv command not using absolute path enables PATH hijacking High 7.3
• CVE-2026-24051 OpenTelemetry-Go Affected by Arbitrary Code Execution via PATH Hijacking High 7.0

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-31303, AZL-33347, AZL-33516, AZL-34580, AZL-34889, AZL-34900 and 20 more.