OpenTelemetry-Go Contrib vulnerable to denial of service in otelhttp due to unbound cardinality metrics

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2023-45142: 1.61% estimated exploitation activity in the next 30 days; percentile 76.02 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary This handler wrapper https://github.com/open-telemetry/opentelemetry-go-contrib/blob/5f7e6ad5a49b45df45f61a1deb29d7f1158032df/instrumentation/net/http/otelhttp/handler.go#L63-L65 out of the box adds labels - http.useragent - http.method that have unbound cardinality. It leads to the server's potential memory exhaustion when many malicious requests are sent to it. Details 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. PoC Send many requests with long randomly generated HTTP methods or/and User agents (e.g. a million) and observe how memory consumption increases during it. Impact In order to be affected, the program has to configure a metrics pipeline, use otelhttp.NewHandler wrapper, and does not filter any unknown HTTP methods or User agents on the level of CDN, LB, previous middleware, etc. Others It is…

Published by the source

16 Oct 2023, 14:01 UTC

Last modified by the source

19 Feb 2024, 03:30 UTC

Source last checked

26 Oct 2026, 15:03 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-rcjv-mgp8-qvmr

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# Patch Next advisory brief: CVE-2023-45142

Advisory: OpenTelemetry-Go Contrib vulnerable to denial of service in otelhttp due to unbound cardinality metrics
IDs: CVE-2023-45142, GHSA-rcjv-mgp8-qvmr
Record: https://patchnext.com/advisories/cve-2023-45142 (revision 1, source checked 26 Oct 2026, 15:03 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: go.opentelemetry.io/contrib/instrumentation/github.com/gin-gonic/gin/otelgin 0.44.0; go.opentelemetry.io/contrib/instrumentation/github.com/gorilla/mux/otelmux 0.44.0; go.opentelemetry.io/contrib/instrumentation/github.com/labstack/echo/otelecho 0.44.0; go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp 0.44.0; go.opentelemetry.io/contrib/instrumentation/github.com/emicklei/go-restful/otelrestful 0.44.0; go.opentelemetry.io/contrib/instrumentation/gopkg.in/macaron.v1/otelmacaron 0.44.0; go.opentelemetry.io/contrib/instrumentation/net/http/httptrace/otelhttptrace 0.44.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go go.opentelemetry.io/contrib/instrumentation/github.com/gin-gonic/gin/otelgin: affected < 0.44.0; fixed in 0.44.0
- Go go.opentelemetry.io/contrib/instrumentation/github.com/gorilla/mux/otelmux: affected < 0.44.0; fixed in 0.44.0
- Go go.opentelemetry.io/contrib/instrumentation/github.com/labstack/echo/otelecho: affected < 0.44.0; fixed in 0.44.0
- Go go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp: affected < 0.44.0; fixed in 0.44.0
- Go go.opentelemetry.io/contrib/instrumentation/github.com/emicklei/go-restful/otelrestful: affected < 0.44.0; fixed in 0.44.0
- Go go.opentelemetry.io/contrib/instrumentation/gopkg.in/macaron.v1/otelmacaron: affected < 0.44.0; fixed in 0.44.0
- Go go.opentelemetry.io/contrib/instrumentation/net/http/httptrace/otelhttptrace: affected < 0.44.0; fixed in 0.44.0

## Suggested inspection (read-only)
- Go go.opentelemetry.io/contrib/instrumentation/github.com/gin-gonic/gin/otelgin: check the installed version with your package manager.
- Go go.opentelemetry.io/contrib/instrumentation/github.com/gorilla/mux/otelmux: check the installed version with your package manager.
- Go go.opentelemetry.io/contrib/instrumentation/github.com/labstack/echo/otelecho: check the installed version with your package manager.
- Go go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp: check the installed version with your package manager.
- Go go.opentelemetry.io/contrib/instrumentation/github.com/emicklei/go-restful/otelrestful: check the installed version with your package manager.
- Go go.opentelemetry.io/contrib/instrumentation/gopkg.in/macaron.v1/otelmacaron: check the installed version with your package manager.
- Go go.opentelemetry.io/contrib/instrumentation/net/http/httptrace/otelhttptrace: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on go.opentelemetry.io/contrib/instrumentation/github.com/gin-gonic/gin/otelgin, go.opentelemetry.io/contrib/instrumentation/github.com/gorilla/mux/otelmux, go.opentelemetry.io/contrib/instrumentation/github.com/labstack/echo/otelecho, go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp, go.opentelemetry.io/contrib/instrumentation/github.com/emicklei/go-restful/otelrestful, go.opentelemetry.io/contrib/instrumentation/gopkg.in/macaron.v1/otelmacaron, go.opentelemetry.io/contrib/instrumentation/net/http/httptrace/otelhttptrace.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-rcjv-mgp8-qvmr (GitHub-reviewed advisory GHSA-rcjv-mgp8-qvmr lists affected ranges: Go go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp >=0 =0 =0 =0 <0.44.0; Go…)

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