{"id":"GHSA-4625-4j76-fww9","revision":null,"records":[{"revision":"bf8c68192f6a4d3b8fe5fe86a64033b0","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-42191","aliases":[],"title":"OpenTelemetry.Exporter.OpenTelemetryProtocol: Disk retry default temp path enables local blob injection for OTLP Exporter","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.","state":0,"publishedAt":"2026-05-12T19:12:03.221+00:00","modifiedAt":"2026-05-13T14:16:18.81+00:00","affected":[{"ecosystem":"Vendor product","name":"opentelemetry-dotnet","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"open-telemetry\",\n                    \"product\": \"opentelemetry-dotnet\",\n                    \"versions\": [\n                        {\n                            \"version\": \">= 1.8.0, < 1.15.3\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L","score":6.5,"severity":"MEDIUM"}],"references":["https://github.com/open-telemetry/opentelemetry-dotnet/security/advisories/GHSA-4625-4j76-fww9","https://github.com/open-telemetry/opentelemetry-dotnet/pull/7106"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-42191","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-42191","identifiers":["CVE-2026-42191"]},"retained":false,"historicalAffected":[]},{"revision":"3e7123f116eb40b0bd33557bd3558ad4","observedAt":"2026-11-07T09:32:28.454+00:00","statement":{"source":"euvd","id":"EUVD-2026-29784","aliases":["CVE-2026-42191","GHSA-4625-4j76-fww9"],"title":"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.GetTempP…","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.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L","score":6.5,"severity":null}],"references":["https://github.com/open-telemetry/opentelemetry-dotnet/security/advisories/GHSA-4625-4j76-fww9","https://github.com/open-telemetry/opentelemetry-dotnet/pull/7106"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-29784","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"May 12, 2026, 7:12:03 PM","dateUpdated":"May 13, 2026, 2:16:18 PM"},"relatedAdvisories":[],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. 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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.","state":0,"publishedAt":"2026-05-12T20:16:41+00:00","modifiedAt":"2026-10-26T18:10:00.173+00:00","affected":[],"metrics":[{"system":"CVSS 3.1 · security-advisories@github.com · Secondary","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L","score":6.5,"severity":"MEDIUM"},{"system":"CVSS 3.1 · nvd@nist.gov · Primary","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://github.com/open-telemetry/opentelemetry-dotnet/pull/7106","https://github.com/open-telemetry/opentelemetry-dotnet/security/advisories/GHSA-4625-4j76-fww9"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-42191","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Analyzed","weaknesses":["CWE-379"],"productCriteria":["cpe:2.3:a:opentelemetry:opentelemetry.exporter.opentelemetryprotocol:*:*:*:*:*:.net:*:*"],"sourceDates":{"published":"2026-05-12T20:16:41.000","lastModified":"2026-10-26T18:10:00.173"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-42191","identifiers":["CVE-2026-42191"]},"retained":false,"historicalAffected":[]},{"revision":"e7da98cd58e944c4a4f4486eb721acec","observedAt":"2026-10-23T16:01:25.029+00:00","statement":{"source":"osv","id":"GHSA-4625-4j76-fww9","aliases":["CVE-2026-42191"],"title":"OpenTelemetry's disk retry default temp path enables local blob injection via OTLP Exporter","description":"### Summary\n\nThe 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.\n\nThe exporter stored and loaded `*.blob` files under fixed, signal-named subdirectories (`traces`, `metrics`, `logs`) beneath that shared temporary root path.\n\nOn multi-user systems where the temporary directory is accessible to other local accounts, this exposed three attack surfaces:\n\n- **Blob injection (integrity):** an attacker could write crafted `*.blob` files into the predictable path; the exporter picks them up on the next retry cycle and forwards them to the configured OTLP endpoint under the application's identity.\n- **Telemetry disclosure (confidentiality):** an attacker reads `*.blob` files written by the application between export failures, recovering encoded telemetry payloads (spans, metric data points, log records).\n- **Resource exhaustion (availability):** an attacker deposits numerous or oversized blob files, degrading retry-loop performance or consuming disk space.\n\n### Details\n\n#### Preconditions\n\n1. `OTEL_DOTNET_EXPERIMENTAL_OTLP_RETRY` is set to `disk`.\n2. `OTEL_DOTNET_EXPERIMENTAL_OTLP_DISK_RETRY_DIRECTORY_PATH` is not set, causing the exporter to resolve the blob storage root using the `System.IO.Path.GetTempPath()` API.\n3. A local attacker has read or write access to the process' temporary directory (e.g., `/tmp` on Linux, or `%TEMP%` on a multi-user Windows installation).\n\n#### Exploit path\n\n1. A target application starts with `OTEL_DOTNET_EXPERIMENTAL_OTLP_RETRY=disk` and no explicit blob directory. The exporter resolves the storage root to `Path.GetTempPath()`, producing paths such as `%TEMP%\\traces`, `%TEMP%\\metrics`, and `%TEMP%\\logs` (or `/tmp/traces` etc. on Linux).\n2. **Injection scenario:** before or during the application's retry window, an attacker writes crafted `*.blob` files into one of those signal subdirectories. On the next retry interval (by default every 60 seconds), [`OtlpExporterPersistentStorageTransmissionHandler`](https://github.com/open-telemetry/opentelemetry-dotnet/blob/c724f4bd6fd88e9a599af1668bf7af9487155b62/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/Transmission/OtlpExporterPersistentStorageTransmissionHandler.cs) scans the directory, loads the attacker-supplied blobs, and forwards them to the configured OTLP endpoint using the application's identity and transport credentials.\n3. **Disclosure scenario:** the attacker reads `*.blob` files that the application wrote after a transient export failure, recovering the full serialized telemetry payloads (spans, metric data points, or log records in Protobuf encoding).\n5. **DoS scenario:** the attacker deposits a large number of oversized blob files in the temporary subdirectories, causing the retry loop to consume excess CPU/IO processing them, potentially exhausting available disk space.\n\n### Mitigations\n\nIf an immediate upgrade to a patched version is not possible:\n\n1. Avoid enabling disk retry in shared environments.\n2. Configure a dedicated directory with strict ACL/ownership and least privilege.\n3. Ensure the directory is not shared across tenants/users.\n4. Monitor for unexpected `*.blob` files or abnormal retry backlog growth.\n\n### Resources\n\n- [#7106](https://github.com/open-telemetry/opentelemetry-dotnet/pull/7106)","state":0,"publishedAt":"2026-04-30T18:34:30+00:00","modifiedAt":"2026-09-10T03:50:43.0132144+00:00","affected":[{"ecosystem":"NuGet","name":"OpenTelemetry.Exporter.OpenTelemetryProtocol","ranges":[{"type":"ECOSYSTEM","events":[{"kind":"introduced","version":"1.8.0"},{"kind":"fixed","version":"1.15.3"}]}],"versions":["1.10.0","1.11.0","1.11.1","1.11.2","1.12.0","1.13.0","1.13.1","1.14.0","1.15.0","1.15.1","1.15.2","1.8.0","1.8.1","1.9.0"],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"MODERATE"}],"references":["https://github.com/open-telemetry/opentelemetry-dotnet/security/advisories/GHSA-4625-4j76-fww9","https://nvd.nist.gov/vuln/detail/CVE-2026-42191","https://github.com/open-telemetry/opentelemetry-dotnet/pull/7106","https://github.com/open-telemetry/opentelemetry-dotnet/commit/78dffdc5ebdf3dc090fdb94e3f1a32d3d1e26dfd","https://github.com/open-telemetry/opentelemetry-dotnet"],"sourceUrl":"https://github.com/advisories/GHSA-4625-4j76-fww9","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-4625-4j76-fww9","identifiers":["GHSA-4625-4j76-fww9","CVE-2026-42191"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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