# CVE-2026-128086: OpenTelemetry-Go: Eager W3C baggage-property materialization causes bounded memory-allocation amplification

Status: published. Published: 2026-11-13. Updated: 2026-11-13.

OpenTelemetry-Go is the Go implementation of OpenTelemetry. From version 1.0.0-RC1 until version 1.47.0, baggage.Parse and propagation.Baggage.Extract eagerly materialize every W3C baggage property through parseMember, grow property slices, serialize members, and copy properties into internal/baggage.Item. A valid densely populated baggage header can therefore cause allocation traffic and retained memory disproportionate to its bounded input size. Remote impact requires baggage extraction to be enabled, attacker-controlled input to reach it, and extraction to run before authentication or on a public route; the evidence establishes increased allocation and garbage-collection pressure but not reliable process termination. This issue is fixed in version 1.47.0.

## Remediation

- fix: go.opentelemetry.io/otel/baggage (Go): OSV reports a fixed version 1.47.0. Check the advisory for supported release branches. (source: OSV GHSA-rrfc-gjm9-cgrj) — https://github.com/advisories/GHSA-rrfc-gjm9-cgrj
- fix: go.opentelemetry.io/otel/propagation (Go): OSV reports a fixed version 1.47.0. Check the advisory for supported release branches. (source: OSV GHSA-rrfc-gjm9-cgrj) — https://github.com/advisories/GHSA-rrfc-gjm9-cgrj

## Affected products and versions

- open-telemetry / opentelemetry-go: >= 1.0.0-RC1, < 1.47.0 (affected). Source: CNA: GitHub_M
-  / go.opentelemetry.io/otel/baggage (go.opentelemetry.io/otel/baggage): ≥ 1.0.0-RC1; < 1.47.0 (affected, semver); OSV events: introduced 1.0.0-RC1; fixed 1.47.0. Source: OSV GHSA-rrfc-gjm9-cgrj
-  / go.opentelemetry.io/otel/propagation (go.opentelemetry.io/otel/propagation): ≥ 1.0.0-RC1; < 1.47.0 (affected, semver); OSV events: introduced 1.0.0-RC1; fixed 1.47.0. Source: OSV GHSA-rrfc-gjm9-cgrj

## Severity and prioritization

- CVSS 3.1: 5.3 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-400, CWE-405

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-rrfc-gjm9-cgrj (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/open-telemetry/opentelemetry-go/pull/9024 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/open-telemetry/opentelemetry-go/commit/f09d1de32f4ac7e5ef16394533721106b1a57b89 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/open-telemetry/opentelemetry-go/releases/tag/v1.47.0 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/advisories/GHSA-rrfc-gjm9-cgrj (OSV / GitHub Security Advisories; advisory)

- https://osv.dev/vulnerability/GHSA-rrfc-gjm9-cgrj (OSV / GitHub Security Advisories; osv)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-128086; retrieved 2026-11-13; source updated 2026-11-13

- OSV / GitHub Security Advisories: https://osv.dev/vulnerability/GHSA-rrfc-gjm9-cgrj; retrieved 2026-11-13; source updated 2026-11-13

Revision: 9ceda217536d60647f6da6bcefb0f6f037a3d42a6b643f1f158d85c736c6fe2f

Canonical: https://y2.dev/cve/CVE-2026-128086

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