CVE-2026-45680

OBI 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.

Details

The vulnerable loop is in pkg/export/prom/prom_bpf.go. During each metrics tick, OBI iterates through probeMetrics and then executes for range metric.count, invoking BpfProbeLatency(...) for each individual recorded hit.

The count comes from calculateStats() in the same file, where deltaCount := bp.runCount - bp.prevRunCount is calculated and returned without any cap before the per-hit replay loop.

If 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.

PoC

Local 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.

Use a vulnerable build and enable internal metrics export:

git checkout v0.0.0-rc.1+build
make build
export OTEL_EBPF_INTERNAL_METRICS_PROMETHEUS_PORT=9090
sudo ./bin/obi

Create a high-rate workload that repeatedly exercises traced probes. For example, generate HTTP traffic against an instrumented service:

python3 -m http.server 18081

Then drive it:

seq 1 500000 | xargs -P 128 -I{} curl -s http://127.0.0.1:18081 >/dev/null

At the same time, scrape metrics repeatedly:

while true; do curl -s http://127.0.0.1:9090/metrics >/dev/null; done

On 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.

This 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.

Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.

CVE-2026-45680 has a CVSS score of 5.9 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.9.0); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-45680? CVE-2026-45680 is a medium-severity uncontrolled resource consumption vulnerability in go.opentelemetry.io/obi (go), affecting versions < 0.9.0. It is fixed in 0.9.0. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
2. How severe is CVE-2026-45680? CVE-2026-45680 has a CVSS score of 5.9 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of go.opentelemetry.io/obi are affected by CVE-2026-45680? go.opentelemetry.io/obi (go) versions < 0.9.0 is affected.
4. Is there a fix for CVE-2026-45680? Yes. CVE-2026-45680 is fixed in 0.9.0. Upgrade to this version or later.
5. Is CVE-2026-45680 exploitable, and should I be worried? Whether CVE-2026-45680 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-45680 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-45680? Upgrade go.opentelemetry.io/obi to 0.9.0 or later.