OpenTelemetry Go up to 1.32.x Attribute Truncation sdk/trace/span.go safeTruncateValidUTF8 denial of service

Summaryinfo

A vulnerability, which was classified as critical, was found in OpenTelemetry Go up to 1.32.x. This affects the function safeTruncateValidUTF8 of the file sdk/trace/span.go of the component Attribute Truncation. The manipulation results in denial of service. This vulnerability was named CVE-2026-81869. The attack may be performed from remote. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in OpenTelemetry Go up to 1.32.x. Affected is the function safeTruncateValidUTF8 of the file sdk/trace/span.go of the component Attribute Truncation. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-81869 since 08/27/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 1.33.0 eliminates this vulnerability.

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Productinfo

Vendor

• OpenTelemetry

Name

• Go

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21
• 1.22
• 1.23
• 1.24
• 1.25
• 1.26
• 1.27
• 1.28
• 1.29
• 1.30
• 1.31
• 1.32

CPE 2.3info

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CPE 2.2info

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