# CVE-2026-128085: opentelemetry-go: AttributeValueLengthLimit is fully bypassed by attribute values composed of valid U+FFFD runes

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

OpenTelemetry-Go is the Go implementation of OpenTelemetry. From SDK version 1.33.0, SDK log version 0.9.0, and trace version 1.35.0 until version 1.47.0, the AttributeValueLengthLimit and WithAttributeValueLengthLimit truncation paths in sdk/internal/attrnorm, sdk/log/internal/attrnorm, and trace/auto.go do not count valid U+FFFD replacement characters. This is a distinct incomplete-fix defect in the replacement truncation code introduced by the remediation for CVE-2026-81869. Values composed of or dominated by those characters can therefore exceed the configured character and memory bound in span, log-record, and auto-instrumentation trace attributes. Attacker-controlled telemetry attributes can increase retained memory and pipeline pressure, while confidentiality and integrity are not affected. This issue is fixed in version 1.47.0.

## Remediation

- fix: go.opentelemetry.io/otel/sdk (Go): OSV reports a fixed version 1.47.0. Check the advisory for supported release branches. (source: OSV GHSA-q7gw-24fr-5p69) — https://github.com/advisories/GHSA-q7gw-24fr-5p69
- fix: go.opentelemetry.io/otel/sdk/log (Go): OSV reports a fixed version 1.47.0. Check the advisory for supported release branches. (source: OSV GHSA-q7gw-24fr-5p69) — https://github.com/advisories/GHSA-q7gw-24fr-5p69
- fix: go.opentelemetry.io/otel/trace (Go): OSV reports a fixed version 1.47.0. Check the advisory for supported release branches. (source: OSV GHSA-q7gw-24fr-5p69) — https://github.com/advisories/GHSA-q7gw-24fr-5p69

## Affected products and versions

- open-telemetry / opentelemetry-go: >= 0.9.0, < 1.47.0 (affected). Source: CNA: GitHub_M
- open-telemetry / go.opentelemetry.io/otel/sdk: >= 1.33.0, < 1.47.0 (affected). Source: CNA: GitHub_M
- open-telemetry / go.opentelemetry.io/otel/sdk: >= 0.9.0, < 1.47.0 (affected). Source: CNA: GitHub_M
- open-telemetry / go.opentelemetry.io/otel/sdk: >= 1.35.0, < 1.47.0 (affected). Source: CNA: GitHub_M
-  / go.opentelemetry.io/otel/sdk (go.opentelemetry.io/otel/sdk): ≥ 1.33.0; < 1.47.0 (affected, semver); OSV events: introduced 1.33.0; fixed 1.47.0. Source: OSV GHSA-q7gw-24fr-5p69
-  / go.opentelemetry.io/otel/sdk/log (go.opentelemetry.io/otel/sdk/log): ≥ 0.9.0; < 1.47.0 (affected, semver); OSV events: introduced 0.9.0; fixed 1.47.0. Source: OSV GHSA-q7gw-24fr-5p69
-  / go.opentelemetry.io/otel/trace (go.opentelemetry.io/otel/trace): ≥ 1.35.0; < 1.47.0 (affected, semver); OSV events: introduced 1.35.0; fixed 1.47.0. Source: OSV GHSA-q7gw-24fr-5p69

## 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-135, CWE-770

## 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-q7gw-24fr-5p69 (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/open-telemetry/opentelemetry-go/commit/017b08c7f1018b619991aaf6b2299d4beb9da1d3 (CNA: GitHub_M; x_refsource_MISC)

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

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

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

- https://github.com/advisories/GHSA-q7gw-24fr-5p69 (OSV / GitHub Security Advisories; advisory)

- https://osv.dev/vulnerability/GHSA-q7gw-24fr-5p69 (OSV / GitHub Security Advisories; osv)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-128085; retrieved 2026-11-13; source updated 2026-11-13

- OSV / GitHub Security Advisories: https://osv.dev/vulnerability/GHSA-q7gw-24fr-5p69; retrieved 2026-11-13; source updated 2026-11-13

Revision: 416fe54935f53d5f0d0b3bfefe7277e832802d72b0684d2b63ea09de67091942

Canonical: https://y2.dev/cve/CVE-2026-128085

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