{"id":"CVE-2026-42191","aliases":["GHSA-4625-4j76-fww9"],"url":"https://o3.security/vulnerability/CVE-2026-42191","summary":"OpenTelemetry.Exporter.OpenTelemetryProtocol: Disk retry default temp path enables local blob injection for OTLP Exporter","details":"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.","published":"2026-05-12T19:12:03.221Z","modified":"2026-07-15T01:48:58.038583864Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"NuGet","name":"OpenTelemetry.Exporter.OpenTelemetryProtocol","fixedVersion":"1.15.3"}],"fix":{"url":"https://github.com/open-telemetry/opentelemetry-dotnet/pull/7106","label":"open-telemetry/opentelemetry-dotnet#7106"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42191.json"},{"type":"ADVISORY","url":"https://github.com/open-telemetry/opentelemetry-dotnet/security/advisories/GHSA-4625-4j76-fww9"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42191"},{"type":"FIX","url":"https://github.com/open-telemetry/opentelemetry-dotnet/pull/7106"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-15T01:48:58.038583864Z"}}