CVE-2026-81871 — otlploggrpc
Fix: open-telemetry/opentelemetry-go@c65d435CVE-2026-81871 is a CWE-295 vulnerability in go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc. A fix is available for go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc — see the affected versions and patch details below.
OpenTelemetry-Go: Log gRPC exporter ignores env TLS certs, bypassing mTLS/pinning
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-81871.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpcReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc | all versions | 0.21.0go get go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc@v0.21.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc to 0.21.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-81871 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-81871 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-81871. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-81871 in your dependencies?
O3 Security finds CVE-2026-81871 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.