CVE-2026-45685: OpenTelemetry eBPF Instrumentation DoS Flaw

CVE-2026-45685 Overview

CVE-2026-45685 is a denial of service vulnerability in OpenTelemetry eBPF Instrumentation, an observability component that captures telemetry from running processes using eBPF probes. The flaw affects versions 0.1.0 through versions prior to 0.9.0. Malformed MongoDB wire protocol messages trigger uncaught panics in the MongoDB TCP parser. A remote unauthenticated attacker can send a single crafted network payload to crash the telemetry agent. The parser processes attacker-controlled bytes before input validation completes, so any reachable instrumented MongoDB endpoint becomes an attack surface. The issue is patched in version 0.9.0. The vulnerability is classified under [CWE-20] Improper Input Validation.

Critical Impact

A single malformed MongoDB wire message terminates telemetry collection for the affected process or node, eliminating visibility for security and operations teams.

Affected Products

• OpenTelemetry eBPF Instrumentation 0.1.0 through versions before 0.9.0
• Go-based deployments using opentelemetry:ebpf_instrumentation
• Any host or container running the affected agent alongside MongoDB traffic

Discovery Timeline

• 2026-06-02 - CVE-2026-45685 published to NVD
• 2026-06-03 - Last updated in NVD database

Technical Details for CVE-2026-45685

Vulnerability Analysis

The OpenTelemetry eBPF Instrumentation agent attaches eBPF probes to monitored processes and decodes application-layer protocols to produce telemetry spans. The MongoDB TCP parser inspects raw wire protocol frames captured from the kernel before applying full structural validation. When the parser encounters malformed length fields, opcode values, or BSON structures, it raises an uncaught Go panic. Because the panic propagates up the parser goroutine without recovery, the agent process terminates. Telemetry collection stops for every workload monitored by that agent instance, creating an observability blackout that may also degrade dependent alerting and incident response workflows.

Root Cause

The root cause is improper input validation in the MongoDB wire protocol decoder. The parser dereferences fields and performs slice operations on attacker-controlled byte ranges before verifying that lengths, offsets, and message types are within expected bounds. The decoder also lacks a recover() boundary around the parsing goroutine, so any panic terminates the entire telemetry process rather than discarding the bad frame.

Attack Vector

An unauthenticated remote attacker sends a crafted TCP payload to a port that an instrumented application reads from or writes to as MongoDB traffic. The eBPF probe captures the bytes from the socket buffer and hands them to the user-space parser. The parser panics on the malformed structure and the agent crashes. No authentication, user interaction, or special privileges are required. Repeated payloads can keep the agent in a crash loop, sustaining the denial of service against telemetry. Technical details are available in the GitHub Security Advisory GHSA-j8p6-96vp-f3r9.

Detection Methods for CVE-2026-45685

Indicators of Compromise

• Unexpected termination or restart of the opentelemetry-ebpf-instrumentation process with Go panic stack traces referencing the MongoDB parser
• Gaps in span ingestion or metric streams correlated with inbound traffic to MongoDB ports (default 27017)
• Repeated systemd, Kubernetes, or container runtime restarts of the instrumentation agent within short intervals

Detection Strategies

• Parse agent logs for Go runtime panic signatures originating in MongoDB protocol decoding functions
• Correlate telemetry pipeline outages with network flow records targeting instrumented MongoDB endpoints
• Alert on agent process exit codes that indicate uncaught panics rather than graceful shutdown

Monitoring Recommendations

• Track agent uptime and restart counts as a first-class service-level indicator
• Monitor MongoDB-bound TCP sessions for malformed wire headers, including invalid messageLength or unknown opCode values
• Forward agent stderr and crash dumps to a centralized logging pipeline for retroactive analysis

How to Mitigate CVE-2026-45685

Immediate Actions Required

• Upgrade OpenTelemetry eBPF Instrumentation to version 0.9.0 or later on every host and container running the agent
• Inventory all deployments that consume the affected Go module to confirm coverage
• Restrict network exposure of instrumented MongoDB endpoints to trusted sources until patching completes

Patch Information

The maintainers fixed the vulnerability in version 0.9.0. Release notes and source artifacts are available at the GitHub Release v0.9.0. The advisory is published as GHSA-j8p6-96vp-f3r9.

Workarounds

• Apply network policies that limit MongoDB port reachability to known application clients
• Disable MongoDB protocol decoding in the agent configuration if upgrading immediately is not feasible
• Run the agent under a supervisor that rate-limits restarts to surface crash-loop conditions to operators

# Upgrade example for Go-based deployments
go get github.com/open-telemetry/opentelemetry-ebpf-instrumentation@v0.9.0
go mod tidy

# Verify installed version
opentelemetry-ebpf-instrumentation --version