OpenTelemetry-Go: Eager W3C baggage-property materialization causes bounded memory-allocation amplification

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

• CVE-2026-128086: 0.44% estimated exploitation activity in the next 30 days; percentile 38.49 (FIRST EPSS, 2026-11-14). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary OpenTelemetry Go eagerly materializes W3C baggage metadata into property objects during parsing. Slice growth, serialization, and copying into the internal representation cause bounded but disproportionate memory-allocation amplification for a valid, densely populated header. In v1.46.0 and v1.47.0-rc.1, the 8,192-byte raw-input limit is checked before member parsing; this is not unlimited allocation or a bypass of that limit. A valid 8,191-byte value containing one member and 4,094 properties causes approximately 778 KB of cumulative allocation per parse. A corrected measurement with forced garbage collection before and after parsing retains approximately 164 KB per result while it remains live. These are different metrics: approximately 95 times the input in allocation traffic versus approximately 20 times in incremental live heap in the measured environment. The relevant security configuration is a service that enables Baggage propagation and extracts…

Published by the source

13 Nov 2026, 19:08 UTC

Last modified by the source

13 Nov 2026, 19:15 UTC

Source last checked

14 Nov 2026, 08:05 UTC

1. Revision 2 · amended · 14 Nov 2026

   Amended from osv record GHSA-rrfc-gjm9-cgrj

2. Revision 1 · created · 13 Nov 2026

   Published from ghsa record GHSA-rrfc-gjm9-cgrj

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# Patch Next advisory brief: CVE-2026-128086

Advisory: OpenTelemetry-Go: Eager W3C baggage-property materialization causes bounded memory-allocation amplification
IDs: CVE-2026-128086, GHSA-rrfc-gjm9-cgrj
Record: https://patchnext.com/advisories/cve-2026-128086 (revision 2, source checked 14 Nov 2026, 08:05 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: go.opentelemetry.io/otel/baggage 1.47.0; go.opentelemetry.io/otel/propagation 1.47.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go go.opentelemetry.io/otel/baggage: affected >= 1.0.0-RC1, < 1.47.0; fixed in 1.47.0
- Go go.opentelemetry.io/otel/propagation: affected >= 1.0.0-RC1, < 1.47.0; fixed in 1.47.0

## Suggested inspection (read-only)
- Go go.opentelemetry.io/otel/baggage: check the installed version with your package manager.
- Go go.opentelemetry.io/otel/propagation: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on go.opentelemetry.io/otel/baggage, go.opentelemetry.io/otel/propagation.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-rrfc-gjm9-cgrj (GitHub-reviewed advisory GHSA-rrfc-gjm9-cgrj lists affected ranges: Go go.opentelemetry.io/otel/baggage >=1.0.0-RC1 =1.0.0-RC1 <1.47.0)
- Verified: https://osv.dev/vulnerability/GHSA-rrfc-gjm9-cgrj (OSV record GHSA-rrfc-gjm9-cgrj lists affected ranges: Go go.opentelemetry.io/otel/baggage >=1.0.0-RC1 =1.0.0-RC1 <1.47.0 (fixed))

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