CVE-2026-81871

MEDIUM CVSS 4.0: 6.3 EPSS 0.20%
Updated Sep 17, 2026
Open-Telemetry
Parameter Value
CVSS 6.3 (MEDIUM)
Fixed In 0.21.0
Type CWE-295 (Improper Certificate Validation), CWE-923
Vendor Open-Telemetry
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
Low
Partial data leak
Integrity
Low
Partial data modification
Availability
None
No disruption

CVSS Vector v4.0

Vulnerable Products

open-telemetry:opentelemetry-go