CVE-2026-39882: opentelemetry-go OTLP HTTP Exporters Read Unbounded Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-w8rr-5gcm-pp58",
  "modified" : "2026-04-09T14:29:37Z",
  "published" : "2026-04-08T19:22:01Z",
  "aliases" : [ "CVE-2026-39882" ],
  "summary" : "opentelemetry-go: OTLP HTTP exporters read unbounded HTTP response bodies",
  "details" : "overview:\nthis report shows that the otlp HTTP exporters (traces/metrics/logs) read the full HTTP response body into an in-memory `bytes.Buffer` without a size cap.\n\nthis is exploitable for memory exhaustion when the configured collector endpoint is attacker-controlled (or a network attacker can mitm the exporter connection).\n\nseverity\n\nHIGH\n\nnot claiming: this is a remote dos against every default deployment.\nclaiming: if the exporter sends traces to an untrusted collector endpoint (or over a network segment where mitm is realistic), that endpoint can crash the process via a large response body.\n\ncallsite (pinned):\n- exporters/otlp/otlptrace/otlptracehttp/client.go:199\n- exporters/otlp/otlptrace/otlptracehttp/client.go:230\n- exporters/otlp/otlpmetric/otlpmetrichttp/client.go:170\n- exporters/otlp/otlpmetric/otlpmetrichttp/client.go:201\n- exporters/otlp/otlplog/otlploghttp/client.go:190\n- exporters/otlp/otlplog/otlploghttp/client.go:221\n\npermalinks (pinned):\n- https://github.com/open-telemetry/opentelemetry-go/blob/248da958375e4dfb4a1105645107be3ef04b1c59/exporters/otlp/otlptrace/otlptracehttp/client.go#L199\n- https://github.com/open-telemetry/opentelemetry-go/blob/248da958375e4dfb4a1105645107be3ef04b1c59/exporters/otlp/otlptrace/otlptracehttp/client.go#L230\n- https://github.com/open-telemetry/opentelemetry-go/blob/248da958375e4dfb4a1105645107be3ef04b1c59/exporters/otlp/otlpmetric/otlpmetrichttp/client.go#L170\n- https://github.com/open-telemetry/opentelemetry-go/blob/248da958375e4dfb4a1105645107be3ef04b1c59/exporters/otlp/otlpmetric/otlpmetrichttp/client.go#L201\n- https://github.com/open-telemetry/opentelemetry-go/blob/248da958375e4dfb4a1105645107be3ef04b1c59/exporters/otlp/otlplog/otlploghttp/client.go#L190\n- https://github.com/open-telemetry/opentelemetry-go/blob/248da958375e4dfb4a1105645107be3ef04b1c59/exporters/otlp/otlplog/otlploghttp/client.go#L221\n\nroot cause:\neach exporter client reads `resp.Body` using `io.Copy(&respData, resp.Body)` into a `bytes.Buffer` on both success and error paths, with no upper bound.\n\nimpact:\na malicious collector can force large transient heap allocations during export (peak memory scales with attacker-chosen response size) and can potentially crash the instrumented process (oom).\n\naffected component:\n- go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp\n- go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp\n- go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp\n\nrepro (local-only):\n\n```bash\nunzip poc.zip -d poc\ncd poc\nmake canonical resp_bytes=33554432 chunk_delay_ms=0\n```\n\nexpected output contains:\n\n```\n[CALLSITE_HIT]: otlptracehttp.UploadTraces::io.Copy(resp.Body)\n[PROOF_MARKER]: resp_bytes=33554432 peak_alloc_bytes=118050512\n```\n\ncontrol (same env, patched target):\n\n```bash\nunzip poc.zip -d poc\ncd poc\nmake control resp_bytes=33554432 chunk_delay_ms=0\n```\n\nexpected control output contains:\n\n```\n[CALLSITE_HIT]: otlptracehttp.UploadTraces::io.Copy(resp.Body)\n[NC_MARKER]: resp_bytes=33554432 peak_alloc_bytes=512232\n```\n\nattachments: poc.zip (attached)\n\n[PR_DESCRIPTION.md](https://github.com/user-attachments/files/25564272/PR_DESCRIPTION.md)\n\n[attack_scenario.md](https://github.com/user-attachments/files/25564273/attack_scenario.md)\n\n[poc.zip](https://github.com/user-attachments/files/25564271/poc.zip)\n\n\nFixed in: https://github.com/open-telemetry/opentelemetry-go/pull/8108",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.43.0"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.43.0"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.19.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-w8rr-5gcm-pp58"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-39882"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/open-telemetry/opentelemetry-go/pull/8108"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/open-telemetry/opentelemetry-go"
  }, {
    "type" : "WEB",
    "url" : "http://github.com/open-telemetry/opentelemetry-go/releases/tag/v1.43.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-789" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-08T19:22:01Z",
    "nvd_published_at" : "2026-04-08T21:17:00Z"
  }
}