CVE-2026-45680: OpenTelemetry eBPF Instrumentation Unbounded BPF Internal Metrics Replay Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-89c6-vpcj-7vj4",
  "modified" : "2026-06-09T10:58:32Z",
  "published" : "2026-05-18T20:11:13Z",
  "aliases" : [ "CVE-2026-45680" ],
  "summary" : "OpenTelemetry eBPF Instrumentation: Unbounded BPF internal metrics replay can exhaust CPU",
  "details" : "### Summary\n\nOBI replays BPF probe hits into histogram observations by looping once per recorded run count. On busy systems, the run-count delta can become very large, causing the metrics exporter to spend excessive CPU time in a tight loop every collection interval.\n\n### Details\n\nThe vulnerable loop is in [pkg/export/prom/prom_bpf.go](https://github.com/open-telemetry/opentelemetry-ebpf-instrumentation/blob/4a39d3b307968df4b54e89b8dee297e7d772ca29/pkg/export/prom/prom_bpf.go#L128-L144). During each metrics tick, OBI iterates through `probeMetrics` and then executes `for range metric.count`, invoking `BpfProbeLatency(...)` for each individual recorded hit.\n\nThe count comes from [`calculateStats()`](https://github.com/open-telemetry/opentelemetry-ebpf-instrumentation/blob/4a39d3b307968df4b54e89b8dee297e7d772ca29/pkg/export/prom/prom_bpf.go#L326-L335) in the same file, where `deltaCount := bp.runCount - bp.prevRunCount` is calculated and returned without any cap before the per-hit replay loop.\n\nIf probe activity spikes between scrape intervals, `deltaCount` can be very large. The exporter then spends CPU time proportional to the number of probe hits rather than the number of metric series.\n\n### PoC\n\nLocal testing with a small reproducer confirmed the replay-loop behavior and showed CPU scaling with the recorded hit count rather than the number of metric series.\n\nUse a vulnerable build and enable internal metrics export:\n\n```bash\ngit checkout v0.0.0-rc.1+build\nmake build\nexport OTEL_EBPF_INTERNAL_METRICS_PROMETHEUS_PORT=9090\nsudo ./bin/obi\n```\n\nCreate a high-rate workload that repeatedly exercises traced probes. For example, generate HTTP traffic against an instrumented service:\n\n```bash\npython3 -m http.server 18081\n```\n\nThen drive it:\n\n```bash\nseq 1 500000 | xargs -P 128 -I{} curl -s http://127.0.0.1:18081 >/dev/null\n```\n\nAt the same time, scrape metrics repeatedly:\n\n```bash\nwhile true; do curl -s http://127.0.0.1:9090/metrics >/dev/null; done\n```\n\nOn a vulnerable build, OBI CPU consumption rises sharply during the metrics loop because histogram updates are replayed once per counted probe execution. The effect is visible in `top` or `pidstat` and is most pronounced under sustained high request volume.\n\n### Impact\n\nThis is an availability issue in the internal metrics path. Any deployment that enables BPF internal metrics and traces busy workloads is affected. Attackers can indirectly consume CPU in the privileged agent by driving enough activity through instrumented services.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "go.opentelemetry.io/obi"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.9.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/open-telemetry/opentelemetry-ebpf-instrumentation/security/advisories/GHSA-89c6-vpcj-7vj4"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-45680"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/open-telemetry/opentelemetry-ebpf-instrumentation"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/open-telemetry/opentelemetry-ebpf-instrumentation/releases/tag/v0.9.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400", "CWE-834" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-18T20:11:13Z",
    "nvd_published_at" : "2026-06-02T16:16:42Z"
  }
}