How severe is GHSA-w34q-cm8f-9c5x?

No CVSS score has been assigned to GHSA-w34q-cm8f-9c5x yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-w34q-cm8f-9c5x?

GHSA-w34q-cm8f-9c5x affects the following packages: go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc (Go). Ecosystems affected: Go.

How do I fix GHSA-w34q-cm8f-9c5x?

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 GHSA-w34q-cm8f-9c5x is resolved across your whole dependency graph.

How do I detect GHSA-w34q-cm8f-9c5x in my Go dependencies?

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.

How do I mitigate GHSA-w34q-cm8f-9c5x if there is no patch (or I can't update yet)?

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 does O3 Security protect against GHSA-w34q-cm8f-9c5x?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-w34q-cm8f-9c5x can be triaged on real exposure rather than presence alone.

Is GHSA-w34q-cm8f-9c5x actively exploited in the wild?

No public exploit code has been indexed for GHSA-w34q-cm8f-9c5x yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-w34q-cm8f-9c5x?

GHSA-w34q-cm8f-9c5x has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 10th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-w34q-cm8f-9c5x?

GHSA-w34q-cm8f-9c5x is classified as CWE-295 (CWE-295), CWE-923 (CWE-923). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-w34q-cm8f-9c5x published, and has it been updated?

GHSA-w34q-cm8f-9c5x was published on September 17, 2026 and was last updated on September 17, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

Not in CISA KEV

GHSA-w34q-cm8f-9c5x — otlploggrpc

Fix: open-telemetry/opentelemetry-go@c65d435

GHSA-w34q-cm8f-9c5x 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

Also known asCVE-2026-81871

Published

Sep 17, 2026

Updated

Sep 17, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 17, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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 GHSA-w34q-cm8f-9c5x.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs10th percentile — riskier than 10% of all scored CVEsHighest risk

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

1 pkg affected

🐹go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc

Real-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

Summary

The OTLP log gRPC exporter loads TLS settings from environment variables but does not apply them when creating gRPC transport credentials. Operators who rely on OTEL_EXPORTER_OTLP_LOGS_CERTIFICATE, OTEL_EXPORTER_OTLP_CERTIFICATE, or related client certificate variables for CA pinning or mTLS get a connection that falls back to system roots and omits the env-supplied client certificate. A network attacker who can intercept or spoof the collector connection with a system-trusted certificate can read or alter log telemetry.

Introduced in commit: d99c76f

Details

The affected code is in exporters/otlp/otlplog/otlploggrpc.

newConfig resolves env-based TLS configuration into cfg.tlsCfg at exporters/otlp/otlplog/otlploggrpc/config.go:106-116. The finding also identifies loadEnvTLS at config.go:451-492 as the code that builds a *tls.Config containing RootCAs and client certificates from OTEL_EXPORTER_OTLP[_LOGS]_CERTIFICATE and OTEL_EXPORTER_OTLP[_LOGS]_CLIENT_CERTIFICATE/KEY.

However, newGRPCDialOptions in exporters/otlp/otlplog/otlploggrpc/client.go:83-92 only checks cfg.gRPCCredentials and cfg.insecure. When neither is set, which is the normal env-only TLS configuration path, it uses credentials.NewTLS(nil). That default trusts the host system root CAs and contains no env-supplied client certificate. The finding evidence reports no other tlsCfg use in the package, so env-based CA pinning and mTLS settings are loaded but not enforced.

PoC

validation-artifact.zip

The validation artifact contains a ready-to-run test at validation-artifact.zip:./poc_env_tls_ignored_test.go and brief instructions at validation-artifact.zip:./README.md.

From a checkout of pellared/opentelemetry-go at commit d99c76f, with Go module dependencies available:

FINDING_DIR=/path/to/02-e6e2897a969c8191b260f243fbc99ebd-log-grpc-exporter-ignores-env-tls-certs-bypassing-mtls-pinning
cd /path/to/opentelemetry-go
git checkout d99c76f
tar -xOf validation-artifact.tar ./poc_env_tls_ignored_test.go > exporters/otlp/otlplog/otlploggrpc/poc_env_tls_ignored_test.go
cd exporters/otlp/otlplog/otlploggrpc
GO111MODULE=on go test -v -run TestEnvTLSIgnored -count=1

The test generates a private CA and a TLS gRPC logs server certificate signed by that CA. It sets:

OTEL_EXPORTER_OTLP_LOGS_ENDPOINT=https://127.0.0.1:<test-port>
OTEL_EXPORTER_OTLP_LOGS_CERTIFICATE=<temp-dir>/ca.pem

Expected output includes an unknown authority failure for the first export call even though the env certificate points to the server CA, followed by a passing test after the same cfg.tlsCfg is explicitly wired through WithTLSCredentials:

=== RUN   TestEnvTLSIgnored
    poc_env_tls_ignored_test.go:...: export error (expected due to ignored tlsCfg): ... x509: certificate signed by unknown authority
--- PASS: TestEnvTLSIgnored
PASS

This demonstrates that the env CA is parsed into cfg.tlsCfg but ignored by the default gRPC dial path.

Impact

This is improper TLS certificate validation and endpoint authentication caused by ignoring configured trust material. Users of the OTLP log gRPC exporter who configure TLS, CA pinning, or mTLS through environment variables are impacted when they do not also supply explicit WithTLSCredentials. TLS still occurs with system roots, but the intended private CA pinning and client certificate authentication are bypassed. An attacker with a suitable network position and a system-trusted certificate for the collector endpoint can intercept or tamper with log telemetry that operators expected to be protected by the configured CA or mTLS policy.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc`	all versions	0.21.0`go get go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc@v0.21.0`

Detection & mitigation playbook

Open-source dependency

Detect
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 GHSA-w34q-cm8f-9c5x 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 GHSA-w34q-cm8f-9c5x can be triaged on real exposure rather than presence alone.

Tailored to GHSA-w34q-cm8f-9c5x. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary The OTLP log gRPC exporter loads TLS settings from environment variables but does not apply them when creating gRPC transport credentials. Operators who rely on `OTEL_EXPORTER_OTLP_LOGS_CERTIFICATE`, `OTEL_EXPORTER_OTLP_CERTIFICATE`, or related client certificate variables for CA pinning or mTLS get a connection that falls back to system roots and omits the env-supplied client certificate. A network attacker who can intercept or spoof the collector connection with a system-trusted certificate can read or alter log telemetry. Introduced in commit: d99c76f ### Details The affect

O3 Security · Impact-Aware SCA

Is GHSA-w34q-cm8f-9c5x in your dependencies?

O3 Security finds GHSA-w34q-cm8f-9c5x across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works