Answer in brief
CVE-2026-81869 records a Medium severity (CVSS 5.1) vulnerability in OpenTelemetry-Go: UTF-8 replacement rune bypasses attribute length truncation. The current sources do not mark it as known exploited. The current feed maps open-telemetry/opentelemetry-go (generic), go.opentelemetry.io/otel/sdk (go), go.opentelemetry.io/otel/sdk (go). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps open-telemetry/opentelemetry-go (generic), go.opentelemetry.io/otel/sdk (go), go.opentelemetry.io/otel/sdk (go). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| open-telemetry/opentelemetry-gogeneric | >=1.10.0 <1.33.0 | 1.33.0 |
| go.opentelemetry.io/otel/sdkgo | >=1.10.0,<1.33.0 | 1.33.0 |
| go.opentelemetry.io/otel/sdkgo | >=1.10.0 <1.33.0 | 1.33.0 |
Published upstream
Sep 16, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 30, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 16, 2026
OpenTelemetry-Go is the Go implementation of OpenTelemetry. From version 1.10.0 until 1.33.0, the sdk/trace/span.go attribute truncation path can fail to enforce AttributeValueLengthLimit for string and string-slice attributes containing the valid Unicode replacement character U+FFFD. safeTruncateValidUTF8 treats the valid replacement rune as invalid UTF-8 and returns the original input, while strings.ToValidUTF8 leaves that valid rune unchanged, so a second safeTruncate attempt can also return the oversized value. An attacker who controls span attribute content can retain values longer than the configured limit, increasing per-span memory use and weakening denial-of-service protection in the instrumented process. This issue is fixed in version 1.33.0.
Quoted source text, attributed separately from HOL analysis.