Executive brief
OpenTelemetry eBPF Instrumentation (OBI) is a tool used to monitor and collect performance data from applications without requiring manual code changes. A vulnerability in its Memcached protocol parser allows a remote attacker to crash the monitoring process by sending a specially crafted request to an instrumented service. This results in a denial of service for the monitoring system, causing a loss of visibility into application performance and health until the process is manually restarted.
Technical details
An integer overflow exists in OBI's Memcached text protocol parser within the `memcachedCommandBytesField` function. When parsing storage commands (e.g., set, add, replace), the parser accepts extremely large `<bytes>` values via `strconv.Atoi` without upper-bound validation. When the parser subsequently adds the length of the payload delimiter (\r\n), the value overflows to a negative integer. This negative length is passed to `LargeBufferReader.Peek`, triggering a Go runtime panic due to an invalid slice bound. An attacker capable of sending Memcached traffic to an instrumented service can remotely crash the OBI process. The issue is fixed in version 0.9.0 by adding proper overflow and bounds checks.
Affected products
- OpenTelemetry OpenTelemetry eBPF Instrumentation (OBI) >= 0.7.0, < 0.9.0
Timeline
- 2026-05-11: patched: Version 0.9.0 released
- 2026-05-12: advisory: GitHub Security Advisory published
- 2026-06-02: disclosed: CVE-2026-45686 published to NVD