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Fencer Intel
medium 6.3

CVE-2026-81871 json

OpenTelemetry-Go: Log gRPC exporter ignores env TLS certs, bypassing mTLS/pinning

published last mo. modified last mo. also EUVD-2026-81262 , GHSA-w34q-cm8f-9c5x , GO-2026-6508

cvss
6.3
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 9%
public exploits
0
none known

Summary

OpenTelemetry-Go is the Go implementation of OpenTelemetry. Prior to version 0.21.0, the exporters/otlp/otlplog/otlploggrpc package loads OTEL_EXPORTER_OTLP_LOGS_CERTIFICATE, OTEL_EXPORTER_OTLP_CERTIFICATE, and related client certificate environment variables through loadEnvTLS into cfg.tlsCfg, but newGRPCDialOptions does not apply cfg.tlsCfg when creating gRPC transport credentials. The environment-only TLS path instead uses credentials.NewTLS with system roots and no configured client certificate, bypassing intended private CA pinning and mutual TLS unless the application also supplies WithTLSCredentials. A network attacker able to intercept or spoof the collector connection with a system-trusted certificate can read or alter log telemetry. This issue is fixed in version 0.21.0.

Patch / fix

  • go go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc 0.21.0
  • linuxfoundation opentelemetry-go 0.21.0
  • opentofu1.12 hummingbird 1 1.12.7-0.1.hum1
  • caddy hummingbird 1 2.11.6-0.1.hum1
  • loki3.7 hummingbird 1 3.7.8-0.2.hum1
  • loki3.7-canary hummingbird 1 3.7.8-0.2.hum1
  • loki3.7-logcli hummingbird 1 3.7.8-0.2.hum1
  • loki3.6 hummingbird 1 3.6.17-0.2.hum1
  • loki3.6-canary hummingbird 1 3.6.17-0.2.hum1
  • loki3.6-logcli hummingbird 1 3.6.17-0.2.hum1

red hat advisories RHSA-2026:74948RHSA-2026:74865RHSA-2026:68941RHSA-2026:68932RHSA-2026:68912RHSA-2026:68926

  • helm SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +10 more 3.22.1-150000.1.104.1
  • helm Linux Micro 6.1 4.3.0-slfo.1.1_1.1
  • distribution SLES for SAP applications 16.0, SLES 16.0 3.1.1-160000.4.1
  • helm SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 4.3.0-160000.1.1

suse advisories SUSE-SU-2026:5119-1SUSE-SU-2026:24282-1SUSE-SU-2026:23990-1SUSE-SU-2026:23973-1SUSE-SU-2026:23984-1

  • alloy openSUSE Tumbleweed 1.20.1-1.1
  • distribution openSUSE Leap 16.0 3.1.1-160000.4.1
  • helm openSUSE Leap 16.0 4.3.0-160000.1.1
  • helm3 openSUSE Tumbleweed 3.22.0-2.1
  • distribution openSUSE Tumbleweed 3.1.1-8.1
  • helm openSUSE Tumbleweed 4.3.0-3.1

opensuse advisories openSUSE-SU-2026:12114-1openSUSE-SU-2026:22010-1openSUSE-SU-2026:21983-1openSUSE-SU-2026:11892-1openSUSE-SU-2026:11872-1openSUSE-SU-2026:11875-1

  • azurelinux-image-tools Azure Linux 3.0 1.7.0-2

azure linux advisories AZL-103110

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Is CVE-2026-81871 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-81871 updated cvss 6.5

go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc: OpenTelemetry-Go: TLS certificate bypass allows log telemetry interception and alteration

  • Red Hat Assisted Installer for Red Hat OpenShift Container Platform 2 assisted/agent-preinstall-image-builder-rhel9 Red Hat Logging Subsystem for Red Hat OpenShift openshift-logging/logging-loki-rhel9, openshift-logging/loki-rhel9-operator
    affected: no fix planned “Out of support scope”
  • Red Hat Multiarch Tuning Operator multiarch-tuning/multiarch-tuning-rhel9-operator, multiarch-tuning/multiarch-tuning-operator-bundle Red Hat Multicluster Engine for Kubernetes multicluster-engine/maestro-rhel9, multicluster-engine/cloudevents-conductor-rhel9 Red Hat Multicluster Global Hub multicluster-globalhub/multicluster-globalhub-grafana-rhel9
    affected: no fix available “Fix deferred”
  • Red Hat OpenShift Developer Tools and Services helm 3.20.2.1-77.el9
    affected: no fix planned “Out of support scope”
  • Red Hat OpenShift Lightspeed openshift-lightspeed/otelcol-lightspeed-rhel9, openshift-lightspeed/lightspeed-agentic-rhel9-operator
    affected: no fix available “Fix deferred”
  • Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/acm-grafana-rhel9, rhacm2/multicluster-operators-subscription-rhel9, rhacm2/acm-multicluster-observability-addon-rhel9
    affected: no fix available, no fix planned “Out of support scope”
  • Red Hat Ceph Storage 5 rhceph/rhceph-5-dashboard-rhel8 Red Hat Ceph Storage 6 rhceph/rhceph-6-dashboard-rhel9
    affected: no fix planned “Out of support scope”
  • Red Hat Ceph Storage 7 rhceph/grafana-rhel9 Red Hat Ceph Storage 8 rhceph/grafana-rhel9
    affected: no fix available “Fix deferred”
  • Red Hat Ceph Storage 9 rhceph/alloy-rhel10, rhceph/grafana-rhel10
    affected: no fix available, no fix planned “Out of support scope”
show 5 more
  • Red Hat Connectivity Link 1 rhcl-1/rhcl-rhel9-operator, rhcl-1/rhcl-operator-bundle, rhcl-tech-preview/mcp-gateway-rhel9, rhcl-tech-preview/mcp-gateway-rhel9-operator Red Hat Edge Manager 1 flightctl 1.2.0-1.el10, rhem/flightctl-api-rhel9, rhem/flightctl-api-rhel10, rhem/flightctl-worker-rhel9, rhem/flightctl-worker-rhel10, rhem/flightctl-db-setup-rhel9, +19 more Red Hat Enterprise Linux 9 opentelemetry-collector, opentelemetry-collector 0.152.1-2.el10_2 Red Hat Enterprise Linux 10 grafana 12.4.3-2.el10, opentelemetry-collector 0.152.1-2.el10_2
    affected: no fix available “Fix deferred”
  • Red Hat Hardened Images opentofu1.11 1.11.14-0.1.hum1
    affected: no fix planned “Will not fix”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-eval-hub-rhel9 Red Hat OpenShift Container Platform 4 openshift4/oc-mirror-plugin-rhel9, openshift4/ose-helm-rhel9-operator Red Hat OpenShift Container Platform 5 openshift5/oc-mirror-plugin-rhel9, openshift5/ose-helm-rhel9-operator Red Hat OpenShift Dev Spaces devspaces/traefik-rhel9 Red Hat OpenShift distributed tracing 3 rhosdt/tempo-rhel9, rhosdt/tempo-query-rhel9, rhosdt/tempo-jaeger-query-rhel9, rhosdt/opentelemetry-rhel9-operator, rhosdt/opentelemetry-collector-rhel9, rhosdt/opentelemetry-target-allocator-rhel9 Red Hat OpenShift GitOps openshift-gitops-1/argocd-rhel8, openshift-gitops-1/argocd-rhel9
    +1 more products
    Red Hat OpenStack Platform 18.0 rhoso-operators/openstack-operator-bundle
    affected: no fix available “Fix deferred”
  • Red Hat Hardened Images helm4 4.3.0-0.2.hum1, caddy 2.11.4-0.4.hum1, caddy 2.11.6-0.1.hum1, helm3 3.22.0-0.2.hum1, jaeger 2.20.0-0.9.hum1, loki3.7 3.7.8-0.2.hum1, +14 more
    fixed: vendor fix RHSA-2026:68715
  • Red Hat Hardened Images opentelemetry-collector 0.152.1-2.el10_2, opentelemetry-collector-k8s 0.160.0-0.1.hum1, opentelemetry-collector-contrib 0.160.0-0.1.hum1
    not affected: component not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
go go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc
<0.21.0
0.21.0

Affected products

  • open-telemetry opentelemetry-go

Classification

Weakness
  • CWE-295 Improper Certificate Validation
  • CWE-923 Improper Restriction of Communication Channel to Intended Endpoints

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.