CVE Catalog

CVE-2026-42191

MediumCVSS 6.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.11%

1th percentile - higher than 1% of all known CVEs

Summary

OpenTelemetry.Exporter.OpenTelemetryProtocol versions 1.8.0 to 1.15.2, when disk retry was enabled without a configured directory path, silently stored and loaded *.blob files under the shared system temporary directory. On multi-user systems this lets other local accounts write crafted blob files, read application blob files, or fill disk space. The issue is fixed in 1.15.3.

Risk Assessment

A local attacker could inject or read data processed by the application and degrade retry-loop performance or exhaust disk space. The risk mainly affects multi-user systems using the OTLP disk retry feature.

Recommendation

Upgrade OpenTelemetry.Exporter.OpenTelemetryProtocol to version 1.15.3 or later. Additionally, explicitly set OTEL_DOTNET_EXPERIMENTAL_OTLP_DISK_RETRY_DIRECTORY_PATH to a directory with appropriate permissions.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS