CVE-2026-81871: open-telemetry opentelemetry-go · Improper Certificate Validation
Affects open-telemetry opentelemetry-goSource CVE Database V5
Not known to be exploited · CVSS 6.3 Medium : upgrade to 0.21.0 when convenient.
Data as of 30 Oct 2026, 20:25 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 0.21.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 16 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade opentelemetry-go and github.com/open-telemetry/opentelemetry-go to 0.21.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| open-telemetryopentelemetry-go | Affected
| Fixed in
|
Gogithub.com/open-telemetry/opentelemetry-gopkg:golang/github.com/open-telemetry/opentelemetry-goOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade to open-telemetry opentelemetry-go version 0.21.0 or later, where this issue is fixed by correctly applying the TLS configuration during gRPC transport credential creation. No other mitigation is indicated by the vendor advisory.
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.
References
- github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-w34q-cm8f-9c5x (opens in a new tab)
- github.com/open-telemetry/opentelemetry-go/commit/c65d435b43e5e6b82310e6b18dd4cdcb8ac63a0c (opens in a new tab)
- github.com/open-telemetry/opentelemetry-go/releases/tag/exporters/otlp/otlplog/otlploggrpc/v0.21.0 (opens in a new tab)