{"url":"http://public2.vulnerablecode.io/api/vulnerabilities/15996?format=json","vulnerability_id":"VCID-f3pj-42yw-fqcp","summary":"OpenTelemetry dotnet: Excessive memory allocation when parsing OpenTelemetry propagation headers\n### Summary\n\nThe implementation details of the baggage, B3 and Jaeger processing code in the `OpenTelemetry.Api` and `OpenTelemetry.Extensions.Propagators` NuGet packages can allocate excessive memory when parsing which could create a potential denial of service (DoS) in the consuming application.\n\n### Details\n\n#### Exceeding Limits\n\n[`BaggagePropagator.Inject<T>()`](https://github.com/open-telemetry/opentelemetry-dotnet/blob/fc1a2864d1665bda857089e11fe9247e3c75637a/src/OpenTelemetry.Api/Context/Propagation/BaggagePropagator.cs#L93-L112) does not enforce the length limit of `8192` characters if the injected baggage contains only one item.\n\nThis change was introduced by #1048.\n\n#### Excessive allocation\n\nThe following methods eagerly allocate intermediate arrays before applying size limits.\n\n- [`BaggagePropagator.Extract<T>()`](https://github.com/open-telemetry/opentelemetry-dotnet/blob/888d1bf2489fb7408d3c5e8758a5bbffa89a8fb2/src/OpenTelemetry.Api/Context/Propagation/BaggagePropagator.cs#L52-L55) - this change was introduced by #1048.\n- [`BaggagePropagator.Inject<T>()`](https://github.com/open-telemetry/opentelemetry-dotnet/blob/888d1bf2489fb7408d3c5e8758a5bbffa89a8fb2/src/OpenTelemetry.Api/Context/Propagation/BaggagePropagator.cs#L138-L157) - this change was introduced by #1048.\n- [`B3Propagator.Extract<T>()`](https://github.com/open-telemetry/opentelemetry-dotnet/blob/888d1bf2489fb7408d3c5e8758a5bbffa89a8fb2/src/OpenTelemetry.Extensions.Propagators/B3Propagator.cs#L203-L207) - this change was introduced by #533.\n- [`B3Propagator.Extract<T>()`](https://github.com/open-telemetry/opentelemetry-dotnet/blob/888d1bf2489fb7408d3c5e8758a5bbffa89a8fb2/src/OpenTelemetry.Api/Context/Propagation/B3Propagator.cs#L204-L214) - this change was introduced by #3244.\n- [`JaegerPropagator.Extract<T>()`](https://github.com/open-telemetry/opentelemetry-dotnet/blob/888d1bf2489fb7408d3c5e8758a5bbffa89a8fb2/src/OpenTelemetry.Extensions.Propagators/JaegerPropagator.cs#L150-L154) - this change was introduced by #3309.\n\n### Impact\n\nExcessively large propagation headers, particularly in degenerate/malformed cases that consist or large numbers of delimiter characters, can allocate excessive amounts of memory for intermediate storage of parsed content relative to the size of the original input.\n\n### Mitigation\n\nHTTP servers often set maximum limits on the length of HTTP request headers, such as [Internet Information Services (IIS)](https://learn.microsoft.com/iis/configuration/system.webserver/security/requestfiltering/requestlimits/headerlimits/) which sets a default limit of 16KB and [nginx](https://nginx.org/docs/http/ngx_http_core_module.html#large_client_header_buffers) which sets a default limit of 8KB.\n\n### Workarounds\n\nPossible workarounds include:\n\n- Configuring appropriate HTTP request header limits.\n- Disabling baggage and/or trace propagation.\n\n### Remediation\n\n[#7061](https://github.com/open-telemetry/opentelemetry-dotnet/pull/7061) refactors the handling of baggage, B3 and Jaeger propagation headers to stop parsing eagerly when limits are exceeded and avoid allocating intermediate arrays.","aliases":[{"alias":"CVE-2026-40894"},{"alias":"GHSA-g94r-2vxg-569j"}],"fixed_packages":[{"url":"http://public2.vulnerablecode.io/api/packages/46937?format=json","purl":"pkg:nuget/OpenTelemetry.Api@1.15.3","is_vulnerable":false,"affected_by_vulnerabilities":[],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:nuget/OpenTelemetry.Api@1.15.3"},{"url":"http://public2.vulnerablecode.io/api/packages/46950?format=json","purl":"pkg:nuget/OpenTelemetry.Extensions.Propagators@1.15.3","is_vulnerable":false,"affected_by_vulnerabilities":[],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:nuget/OpenTelemetry.Extensions.Propagators@1.15.3"}],"affected_packages":[],"references":[{"reference_url":"https://api.first.org/data/v1/epss?cve=CVE-2026-40894","reference_id":"","reference_type":"","scores":[{"value":"0.00028","scoring_system":"epss","scoring_elements":"0.0854","published_at":"2026-05-29T12:55:00Z"}],"url":"https://api.first.org/data/v1/epss?cve=CVE-2026-40894"},{"reference_url":"https://github.com/open-telemetry/opentelemetry-dotnet","reference_id":"","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/open-telemetry/opentelemetry-dotnet"},{"reference_url":"https://github.com/open-telemetry/opentelemetry-dotnet/pull/1048","reference_id":"","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""},{"value":"Track","scoring_system":"ssvc","scoring_elements":"SSVCv2/E:N/A:Y/T:P/P:M/B:A/M:M/D:T/2026-04-23T19:22:40Z/"}],"url":"https://github.com/open-telemetry/opentelemetry-dotnet/pull/1048"},{"reference_url":"https://github.com/open-telemetry/opentelemetry-dotnet/pull/3244","reference_id":"","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""},{"value":"Track","scoring_system":"ssvc","scoring_elements":"SSVCv2/E:N/A:Y/T:P/P:M/B:A/M:M/D:T/2026-04-23T19:22:40Z/"}],"url":"https://github.com/open-telemetry/opentelemetry-dotnet/pull/3244"},{"reference_url":"https://github.com/open-telemetry/opentelemetry-dotnet/pull/3309","reference_id":"","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""},{"value":"Track","scoring_system":"ssvc","scoring_elements":"SSVCv2/E:N/A:Y/T:P/P:M/B:A/M:M/D:T/2026-04-23T19:22:40Z/"}],"url":"https://github.com/open-telemetry/opentelemetry-dotnet/pull/3309"},{"reference_url":"https://github.com/open-telemetry/opentelemetry-dotnet/pull/3533","reference_id":"","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/open-telemetry/opentelemetry-dotnet/pull/3533"},{"reference_url":"https://github.com/open-telemetry/opentelemetry-dotnet/pull/533","reference_id":"","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""},{"value":"Track","scoring_system":"ssvc","scoring_elements":"SSVCv2/E:N/A:Y/T:P/P:M/B:A/M:M/D:T/2026-04-23T19:22:40Z/"}],"url":"https://github.com/open-telemetry/opentelemetry-dotnet/pull/533"},{"reference_url":"https://github.com/open-telemetry/opentelemetry-dotnet/pull/7061","reference_id":"","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""},{"value":"Track","scoring_system":"ssvc","scoring_elements":"SSVCv2/E:N/A:Y/T:P/P:M/B:A/M:M/D:T/2026-04-23T19:22:40Z/"}],"url":"https://github.com/open-telemetry/opentelemetry-dotnet/pull/7061"},{"reference_url":"https://github.com/open-telemetry/opentelemetry-dotnet/releases/tag/core-1.15.3","reference_id":"","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/open-telemetry/opentelemetry-dotnet/releases/tag/core-1.15.3"},{"reference_url":"https://github.com/open-telemetry/opentelemetry-dotnet/security/advisories/GHSA-g94r-2vxg-569j","reference_id":"","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS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