OpenTelemetry-Go: UTF-8 replacement rune bypasses attribute length truncation

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-81869
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-16 21:17:22 UTC
Updated2026-09-17 15:16:52 UTC
DescriptionOpenTelemetry-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.

Risk And Classification

Primary CVSS: v4.0 5.1 MEDIUM from [email protected]

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-176 | CWE-400 | CWE-176 CWE-176: Improper Handling of Unicode Encoding | CWE-400 CWE-400: Uncontrolled Resource Consumption

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary5.1MEDIUMCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/C...
4.0CNADECLARED5.1MEDIUMCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Open-telemetry Opentelemetry-go affected >= 1.10.0, < 1.33.0 Not specified

References

ReferenceSourceLinkTags
github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-p9f8... 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/open-telemetry/opentelemetry-go/pull/5997 [email protected] github.com
github.com/open-telemetry/opentelemetry-go/commit/e016a78c9f5b24a1c2beea... [email protected] github.com
github.com/open-telemetry/opentelemetry-go/issues/5996 [email protected] github.com
github.com/open-telemetry/opentelemetry-go/releases/tag/sdk/v1.33.0 [email protected] github.com
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