{"id":"CVE-2026-42348","aliases":["EUVD-2026-29706","GHSA-w2jh-77fq-7gp8"],"status":"published","title":"OpAMP client reads unbounded HTTP response bodies","description":"OpenTelemetry.OpAmp.Client is the OpAMP client for OpenTelemetry .NET. Prior to 0.2.0-alpha.1, when receiving responses from the OpAMP server over HTTP, the OpAMP client allocates an unbounded buffer to read all bytes from the server, with no upper-bound on the number of bytes consumed. This could cause memory exhaustion in the consuming application if the configured OpAMP server is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned in the response. This vulnerability is fixed in 0.2.0-alpha.1.","severity":{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00311,"percentile":0.24223,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-789"],"published":"2026-05-05T21:57:54Z","modified":"2026-10-28T02:30:55Z","fixes":[{"ecosystem":"NuGet","package":"OpenTelemetry.OpAmp.Client","fixed_in":["0.2.0-alpha.1"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"NuGet","package":"OpenTelemetry.OpAmp.Client","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.2.0-alpha.1"}]}]},{"source":"osv","ecosystem":"NuGet","package":"OpenTelemetry.OpAmp.Client","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.2.0-alpha.1"}]}]}],"products":[{"vendor":"open-telemetry","product":"opentelemetry-dotnet-contrib"},{"vendor":"opentelemetry","product":"opentelemetry.opamp.client"}],"references":[{"url":"https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-w2jh-77fq-7gp8","tags":["x_refsource_CONFIRM","Patch","Vendor Advisory","advisory","web"]},{"url":"https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4116","tags":["x_refsource_MISC","Issue Tracking","fix","web"]},{"url":"https://github.com/open-telemetry/opentelemetry-dotnet-contrib/commit/bf1fad4fa298ff451cda0efb0ee9c7a7eb46212a","tags":["web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42348","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-w2jh-77fq-7gp8"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42348.json","tags":["advisory"]},{"url":"https://github.com/open-telemetry/opentelemetry-dotnet-contrib","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-42348","title":"OpAMP client reads unbounded HTTP response bodies","description":"OpenTelemetry.OpAmp.Client is the OpAMP client for OpenTelemetry .NET. Prior to 0.2.0-alpha.1, when receiving responses from the OpAMP server over HTTP, the OpAMP client allocates an unbounded buffer to read all bytes from the server, with no upper-bound on the number of bytes consumed. This could cause memory exhaustion in the consuming application if the configured OpAMP server is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned in the response. This vulnerability is fixed in 0.2.0-alpha.1.","status":"published","published":"2026-05-12T18:01:41.812Z","modified":"2026-05-13T19:32:28.404Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-789"],"updated_at":"2026-11-02T13:40:23.731501Z"}],"euvd":[{"id":"EUVD-2026-29706","description":"OpenTelemetry.OpAmp.Client is the OpAMP client for OpenTelemetry .NET. Prior to 0.2.0-alpha.1, when receiving responses from the OpAMP server over HTTP, the OpAMP client allocates an unbounded buffer to read all bytes from the server, with no upper-bound on the number of bytes consumed. This could cause memory exhaustion in the consuming application if the configured OpAMP server is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned in the response. This vulnerability is fixed in 0.2.0-alpha.1.","status":"published","published":"2026-05-12T18:01:41Z","modified":"2026-05-13T19:32:28Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T19:04:32.516693Z"}],"ghsa":[{"id":"GHSA-w2jh-77fq-7gp8","title":"OpAMP client reads unbounded HTTP response bodies","description":"### Summary\n\nWhen receiving responses from the OpAMP server over HTTP, the OpAMP client allocates an unbounded buffer to read all bytes from the server, with no upper-bound on the number of bytes consumed.\n\nThis could cause memory exhaustion in the consuming application if the configured OpAMP server is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned in the response. \n\n### Details\n\n[#2926](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/2926) introduced the initial HTTP transport components which uses `ReadAsByteArrayAsync` to copy the `HttpResponseMessage.Content` into a byte array. This code path allows an unbounded read of the entire HTTP response message.\n\n### Impact\n\nIf an application using the OpAMP client is configured to use an OpAMP server that is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned in the response, the application could have its memory exhausted and create a denial-of-service condition.\n\n### Mitigation\n\nThe application's configured OpAMP server needs to behave maliciously. If the OpAMP server is a well-behaved implementation, response bodies should not be excessively large.\n\n### Workarounds\n\nNone known.\n\n### Remediation\n\n[#4116](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4116) updates the OpAMP client HTTP transport to limit the maximum size of responses to 128KB.\n\n### Resources\n\n- [#2926](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/2926)\n- [#4116](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4116)\n- [CWE-789](https://cwe.mitre.org/data/definitions/789.html)","status":"published","published":"2026-05-05T21:57:54Z","modified":"2026-05-13T16:27:09Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-789"],"updated_at":"2026-11-02T14:40:09.033429Z"}],"nvd":[{"id":"CVE-2026-42348","description":"OpenTelemetry.OpAmp.Client is the OpAMP client for OpenTelemetry .NET. Prior to 0.2.0-alpha.1, when receiving responses from the OpAMP server over HTTP, the OpAMP client allocates an unbounded buffer to read all bytes from the server, with no upper-bound on the number of bytes consumed. This could cause memory exhaustion in the consuming application if the configured OpAMP server is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned in the response. This vulnerability is fixed in 0.2.0-alpha.1.","status":"published","published":"2026-05-12T18:17:24.7Z","modified":"2026-10-26T18:10:00.173Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"}],"cwes":["CWE-789"],"updated_at":"2026-11-02T14:12:18.613259Z"}],"osv":[{"id":"CVE-2026-42348","title":"OpAMP client reads unbounded HTTP response bodies","description":"OpenTelemetry.OpAmp.Client is the OpAMP client for OpenTelemetry .NET. Prior to 0.2.0-alpha.1, when receiving responses from the OpAMP server over HTTP, the OpAMP client allocates an unbounded buffer to read all bytes from the server, with no upper-bound on the number of bytes consumed. This could cause memory exhaustion in the consuming application if the configured OpAMP server is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned in the response. This vulnerability is fixed in 0.2.0-alpha.1.","status":"published","published":"2026-05-12T18:01:41.812Z","modified":"2026-10-28T02:30:55.04803783Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-789"],"updated_at":"2026-11-02T15:45:04.117819Z"},{"id":"GHSA-w2jh-77fq-7gp8","title":"OpAMP client reads unbounded HTTP response bodies","description":"### Summary\n\nWhen receiving responses from the OpAMP server over HTTP, the OpAMP client allocates an unbounded buffer to read all bytes from the server, with no upper-bound on the number of bytes consumed.\n\nThis could cause memory exhaustion in the consuming application if the configured OpAMP server is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned in the response. \n\n### Details\n\n[#2926](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/2926) introduced the initial HTTP transport components which uses `ReadAsByteArrayAsync` to copy the `HttpResponseMessage.Content` into a byte array. This code path allows an unbounded read of the entire HTTP response message.\n\n### Impact\n\nIf an application using the OpAMP client is configured to use an OpAMP server that is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned in the response, the application could have its memory exhausted and create a denial-of-service condition.\n\n### Mitigation\n\nThe application's configured OpAMP server needs to behave maliciously. If the OpAMP server is a well-behaved implementation, response bodies should not be excessively large.\n\n### Workarounds\n\nNone known.\n\n### Remediation\n\n[#4116](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4116) updates the OpAMP client HTTP transport to limit the maximum size of responses to 128KB.\n\n### Resources\n\n- [#2926](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/2926)\n- [#4116](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4116)\n- [CWE-789](https://cwe.mitre.org/data/definitions/789.html)","status":"published","published":"2026-05-05T21:57:54Z","modified":"2026-05-13T16:46:20.709201Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-789"],"updated_at":"2026-11-02T15:46:58.04805Z"}]}}