---
id: CVE-2026-81869
title: OpenTelemetry-Go is the Go implementation of OpenTelemetry
summary: >-
  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…
severity: medium
cvss: 5.1
cvssVector: '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'
cwe:
  - CWE-176
  - CWE-400
vendor: open-telemetry
product: opentelemetry-go
affected:
  - 'opentelemetry-go >= 1.10.0, < 1.33.0'
published: '2026-09-16'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T15:16:52.823'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-81869'
references:
  - url: >-
      https://github.com/open-telemetry/opentelemetry-go/commit/e016a78c9f5b24a1c2beeaad47686c2f2213f49a
    label: security-advisories@github.com
  - url: 'https://github.com/open-telemetry/opentelemetry-go/issues/5996'
    label: security-advisories@github.com
  - url: 'https://github.com/open-telemetry/opentelemetry-go/pull/5997'
    label: security-advisories@github.com
  - url: >-
      https://github.com/open-telemetry/opentelemetry-go/releases/tag/sdk/v1.33.0
    label: security-advisories@github.com
  - url: >-
      https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-p9f8-wvj8-2fg8
    label: security-advisories@github.com
  - url: >-
      https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-p9f8-wvj8-2fg8
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-81869.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-81869'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-81869'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-81869'
tags:
  - nvd
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-17T14:15:41.862542Z'
cvssSource: cna
ingestedAt: '2026-09-16T21:05:36.880Z'
scores:
  cna: 5.1
  vendor: 4
epss: 0.0018
epssPercentile: 0.06684
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-81869.json)