CVE-2026-42191
6.5 · MEDIUMOverview
CVE-2026-42191 is a medium-severity vulnerability affecting opentelemetry opentelemetry.exporter.opentelemetryprotocol. It was published on May 12, 2026 and has a CVSS 3.1 base score of 6.5 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical Description
OpenTelemetry.Exporter.OpenTelemetryProtocol is the OTLP (OpenTelemetry Protocol) exporter implementation. From 1.8.0 to 1.15.2, the OTLP disk retry feature in OpenTelemetry.Exporter.OpenTelemetryProtocol silently fell back to Path.GetTempPath() when OTEL_DOTNET_EXPERIMENTAL_OTLP_RETRY=disk was set but OTEL_DOTNET_EXPERIMENTAL_OTLP_DISK_RETRY_DIRECTORY_PATH was not configured. The exporter stored and loaded *.blob files under fixed, signal-named subdirectories (traces, metrics, logs) beneath that shared temporary root path. On multi-user systems where the temporary directory is accessible to other local accounts, this allows an attacker to write crafted *.blob files, read *.blob files written by the application between export failures, or deposit numerous or oversized blob files, degrading retry-loop performance or consuming disk space. This vulnerability is fixed in 1.15.3.
Remediation
Check the references section for vendor advisories and patches from opentelemetry. Update opentelemetry.exporter.opentelemetryprotocol to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| opentelemetry | opentelemetry.exporter.opentelemetryprotocol | >= 1.8.0, < 1.15.3 | Affected |
Frequently Asked Questions
What is CVE-2026-42191?
CVE-2026-42191 is a medium-severity vulnerability affecting opentelemetry opentelemetry.exporter.opentelemetryprotocol. It was published on May 12, 2026 and has a CVSS 3.1 base score of 6.5 (MEDIUM).
How severe is CVE-2026-42191?
This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2026-42191?
Check the references section for vendor advisories and patches from opentelemetry. Update opentelemetry.exporter.opentelemetryprotocol to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-42191?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-42191 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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