{"id":"CVE-2026-81869","state":"PUBLISHED","title":"OpenTelemetry-Go: UTF-8 replacement rune bypasses attribute length truncation","description":"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.","publishedAt":"2026-09-16T20:41:15.806Z","updatedAt":"2026-09-17T14:15:51.501Z","severity":{"score":5.1,"label":"Medium","version":"4.0","vector":"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","source":"GitHub_M"},"assigner":"GitHub_M","products":["open-telemetry opentelemetry-go"],"affected":[{"vendor":"open-telemetry","product":"opentelemetry-go","versions":[{"version":">= 1.10.0, < 1.33.0","status":"affected"}]}],"references":["https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-p9f8-wvj8-2fg8","https://github.com/open-telemetry/opentelemetry-go/issues/5996","https://github.com/open-telemetry/opentelemetry-go/pull/5997","https://github.com/open-telemetry/opentelemetry-go/commit/e016a78c9f5b24a1c2beeaad47686c2f2213f49a","https://github.com/open-telemetry/opentelemetry-go/releases/tag/sdk/v1.33.0"],"weaknesses":["CWE-176","CWE-400"],"ingestedAt":"2026-10-29T20:13:15.269Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/81xxx/CVE-2026-81869.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-81869","state":"PUBLISHED","datePublished":"2026-09-16T20:41:15.806Z","dateUpdated":"2026-09-17T14:15:51.501Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-08-27T17:48:42.120Z"},"containers":{"cna":{"title":"OpenTelemetry-Go: UTF-8 replacement rune bypasses attribute length truncation","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"open-telemetry","product":"opentelemetry-go","versions":[{"version":">= 1.10.0, < 1.33.0","status":"affected"}]}],"references":[{"url":"https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-p9f8-wvj8-2fg8","name":"https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-p9f8-wvj8-2fg8","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/open-telemetry/opentelemetry-go/issues/5996","name":"https://github.com/open-telemetry/opentelemetry-go/issues/5996","tags":["x_refsource_MISC"]},{"url":"https://github.com/open-telemetry/opentelemetry-go/pull/5997","name":"https://github.com/open-telemetry/opentelemetry-go/pull/5997","tags":["x_refsource_MISC"]},{"url":"https://github.com/open-telemetry/opentelemetry-go/commit/e016a78c9f5b24a1c2beeaad47686c2f2213f49a","name":"https://github.com/open-telemetry/opentelemetry-go/commit/e016a78c9f5b24a1c2beeaad47686c2f2213f49a","tags":["x_refsource_MISC"]},{"url":"https://github.com/open-telemetry/opentelemetry-go/releases/tag/sdk/v1.33.0","name":"https://github.com/open-telemetry/opentelemetry-go/releases/tag/sdk/v1.33.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"LOCAL","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"LOW","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":5.1,"baseSeverity":"MEDIUM","vectorString":"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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-176","lang":"en","description":"CWE-176: Improper Handling of Unicode Encoding","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-400","lang":"en","description":"CWE-400: Uncontrolled Resource Consumption","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-16T20:41:15.806Z"},"source":{"advisory":"GHSA-p9f8-wvj8-2fg8","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-p9f8-wvj8-2fg8","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-17T14:15:41.862542Z","id":"CVE-2026-81869","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-17T14:15:51.501Z"}}]}}}