GHSA-W8RR-5GCM-PP58

Vulnerability from github – Published: 2026-04-08 19:22 – Updated: 2026-04-09 14:29
VLAI?
Summary
opentelemetry-go: OTLP HTTP exporters read unbounded HTTP response bodies
Details

overview: this 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.

this is exploitable for memory exhaustion when the configured collector endpoint is attacker-controlled (or a network attacker can mitm the exporter connection).

severity

HIGH

not claiming: this is a remote dos against every default deployment. claiming: 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.

callsite (pinned): - exporters/otlp/otlptrace/otlptracehttp/client.go:199 - exporters/otlp/otlptrace/otlptracehttp/client.go:230 - exporters/otlp/otlpmetric/otlpmetrichttp/client.go:170 - exporters/otlp/otlpmetric/otlpmetrichttp/client.go:201 - exporters/otlp/otlplog/otlploghttp/client.go:190 - exporters/otlp/otlplog/otlploghttp/client.go:221

permalinks (pinned): - https://github.com/open-telemetry/opentelemetry-go/blob/248da958375e4dfb4a1105645107be3ef04b1c59/exporters/otlp/otlptrace/otlptracehttp/client.go#L199 - https://github.com/open-telemetry/opentelemetry-go/blob/248da958375e4dfb4a1105645107be3ef04b1c59/exporters/otlp/otlptrace/otlptracehttp/client.go#L230 - https://github.com/open-telemetry/opentelemetry-go/blob/248da958375e4dfb4a1105645107be3ef04b1c59/exporters/otlp/otlpmetric/otlpmetrichttp/client.go#L170 - https://github.com/open-telemetry/opentelemetry-go/blob/248da958375e4dfb4a1105645107be3ef04b1c59/exporters/otlp/otlpmetric/otlpmetrichttp/client.go#L201 - https://github.com/open-telemetry/opentelemetry-go/blob/248da958375e4dfb4a1105645107be3ef04b1c59/exporters/otlp/otlplog/otlploghttp/client.go#L190 - https://github.com/open-telemetry/opentelemetry-go/blob/248da958375e4dfb4a1105645107be3ef04b1c59/exporters/otlp/otlplog/otlploghttp/client.go#L221

root cause: each 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.

impact: a 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).

affected component: - go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp - go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp - go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp

repro (local-only):

unzip poc.zip -d poc
cd poc
make canonical resp_bytes=33554432 chunk_delay_ms=0

expected output contains:

[CALLSITE_HIT]: otlptracehttp.UploadTraces::io.Copy(resp.Body)
[PROOF_MARKER]: resp_bytes=33554432 peak_alloc_bytes=118050512

control (same env, patched target):

unzip poc.zip -d poc
cd poc
make control resp_bytes=33554432 chunk_delay_ms=0

expected control output contains:

[CALLSITE_HIT]: otlptracehttp.UploadTraces::io.Copy(resp.Body)
[NC_MARKER]: resp_bytes=33554432 peak_alloc_bytes=512232

attachments: poc.zip (attached)

PR_DESCRIPTION.md

attack_scenario.md

poc.zip

Fixed in: https://github.com/open-telemetry/opentelemetry-go/pull/8108

Severity ?
5.3 (Medium)
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.43.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.43.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.19.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-39882"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-789"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-08T19:22:01Z",
    "nvd_published_at": "2026-04-08T21:17:00Z",
    "severity": "MODERATE"
  },
  "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(\u0026respData, 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",
  "id": "GHSA-w8rr-5gcm-pp58",
  "modified": "2026-04-09T14:29:37Z",
  "published": "2026-04-08T19:22:01Z",
  "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"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "opentelemetry-go: OTLP HTTP exporters read unbounded HTTP response bodies"
}


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