{"id":"EUVD-2026-81260","revision":null,"records":[{"revision":"b24c8bd564dc471fba8ee96b59fa9b8a","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-81869","aliases":[],"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.","state":0,"publishedAt":"2026-09-16T20:41:15.806+00:00","modifiedAt":"2026-09-17T14:15:51.501+00:00","affected":[{"ecosystem":"Vendor product","name":"opentelemetry-go","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"open-telemetry\",\n                    \"product\": \"opentelemetry-go\",\n                    \"versions\": [\n                        {\n                            \"version\": \">= 1.10.0, < 1.33.0\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 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","score":5.1,"severity":"MEDIUM"}],"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"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-81869","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-81869","identifiers":["CVE-2026-81869"]},"retained":false,"historicalAffected":[]},{"revision":"31b80721a0964aa89bcc5af8c33556d1","observedAt":"2026-11-11T16:10:29.206+00:00","statement":{"source":"euvd","id":"EUVD-2026-81260","aliases":["CVE-2026-81869","GHSA-p9f8-wvj8-2fg8"],"title":"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 th…","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.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 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","score":5.1,"severity":null}],"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"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-81260","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Sep 16, 2026, 8:41:15 PM","dateUpdated":"Sep 17, 2026, 2:15:51 PM"},"relatedAdvisories":[],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. 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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.","state":0,"publishedAt":"2026-09-16T21:17:22.18+00:00","modifiedAt":"2026-09-30T17:43:24.057+00:00","affected":[],"metrics":[{"system":"CVSS 4.0 · security-advisories@github.com · Secondary","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/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","score":5.1,"severity":"MEDIUM"}],"references":["https://github.com/open-telemetry/opentelemetry-go/commit/e016a78c9f5b24a1c2beeaad47686c2f2213f49a","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/releases/tag/sdk/v1.33.0","https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-p9f8-wvj8-2fg8"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-81869","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Awaiting Analysis","weaknesses":["CWE-176","CWE-400"],"productCriteria":[],"sourceDates":{"published":"2026-09-16T21:17:22.180","lastModified":"2026-09-30T17:43:24.057"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-81869","identifiers":["CVE-2026-81869"]},"retained":false,"historicalAffected":[]},{"revision":"b218aea3665e41048ddbfb9985a85a96","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GHSA-p9f8-wvj8-2fg8","aliases":["CVE-2026-81869","GO-2026-6616"],"title":"OpenTelemetry-Go: UTF-8 replacement rune bypasses attribute length truncation","description":"### Summary\n\nThe OpenTelemetry Go SDK trace package can fail to enforce `AttributeValueLengthLimit` for string attributes containing the valid Unicode replacement character U+FFFD. An oversized attacker-controlled attribute value that includes U+FFFD is returned untruncated, bypassing the configured memory/DoS protection and allowing increased per-span memory usage. The finding is low severity because it requires a deployment with attribute value length limits enabled and attacker-controlled data being recorded into span attributes.\n\nIntroduced in commit 49a6536\n\n### Details\n\nString and string-slice span attributes are truncated through `safeTruncate` when `AttributeValueLengthLimit` is non-negative. The finding evidence identifies this enforcement path in `sdk/trace/span.go:303-331`, with string attributes passed to `safeTruncate` at `sdk/trace/span.go:309-310` and string-slice entries passed to `safeTruncate` in the loop beginning at `sdk/trace/span.go:312`.\n\n`safeTruncate` first calls `safeTruncateValidUTF8`; if that returns `ok=false`, it calls `strings.ToValidUTF8(input, \"\")` and retries. The relevant code is identified in `sdk/trace/span.go:337-355`. `safeTruncateValidUTF8` treats any `utf8.RuneError` from `utf8.DecodeRuneInString` as invalid UTF-8 and immediately returns the original input with `ok=false`. However, Go also returns `utf8.RuneError` for a valid encoded U+FFFD rune. The validation artifact confirms this behavior with output `r=U+FFFD size=3 runeError=true`.\n\nFor an input such as `\"AAAA\" + U+FFFD + strings.Repeat(\"B\", 20)` and a limit of 5, the first truncation attempt sees U+FFFD as `utf8.RuneError` and returns the full input with `ok=false`. `strings.ToValidUTF8` does not remove the valid U+FFFD rune, so the second attempt returns the same full input. As a result, the span attribute value remains 27 bytes long even though the configured limit is 5.\n\n### PoC\n\n[validation-artifact.zip](https://github.com/user-attachments/files/27494267/validation-artifact.zip)\n\n\nThe validation artifact contains a package-level Go test at `validation-artifact.tar:safe_truncate_bypass/safe_truncate_poc_test.go` and supporting output at `validation-artifact.tar:safe_truncate_bypass/runecheck_output.txt`.\n\nReproduction configuration:\n- Repository: `pellared/opentelemetry-go`\n- Commit: `49a6536` from September 12, 2022\n- Package/module path: `sdk/trace` under the `sdk` module\n- Attribute value length limit used by the PoC: `limit := 5`\n- Dependencies must be available through the network or a local module cache/vendor directory.\n\nCommands:\n```sh\ncd /path/to/opentelemetry-go\ngit checkout 49a6536\ntar -xOf /path/to/validation-artifact.tar safe_truncate_bypass/safe_truncate_poc_test.go > sdk/trace/safe_truncate_poc_test.go\ncd sdk\ngo test ./trace -run TestSafeTruncateBypass -count=1 -v\n```\n\nExpected vulnerable output includes a failing test showing that the returned value exceeds the configured limit:\n```text\n=== RUN   TestSafeTruncateBypass\n    safe_truncate_poc_test.go:14: input_len=27 got_len=27 input=\"AAAA�BBBBBBBBBBBBBBBBBBBB\" got=\"AAAA�BBBBBBBBBBBBBBBBBBBB\"\n    safe_truncate_poc_test.go:16: bypass: got_len 27 > limit 5\n--- FAIL: TestSafeTruncateBypass\n```\n\nThe artifact also records the standalone UTF-8 behavior needed for the bypass:\n```sh\ntar -xOf /path/to/validation-artifact.tar safe_truncate_bypass/runecheck_output.txt\n```\n\nExpected output:\n```text\nr=U+FFFD size=3 runeError=true\n```\n\n### Impact\n\nThis is a Unicode handling and resource-limit bypass that weakens span attribute memory controls. Applications that enable `AttributeValueLengthLimit` to bound memory usage can still store oversized attacker-controlled attribute values if those values contain U+FFFD. The practical impact is increased memory use and reduced denial-of-service protection in the instrumented process; the finding does not show confidentiality or integrity impact.","state":0,"publishedAt":"2026-09-29T17:59:10+00:00","modifiedAt":"2026-10-01T20:56:23.8771008+00:00","affected":[{"ecosystem":"Go","name":"go.opentelemetry.io/otel/sdk","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"1.10.0"},{"kind":"fixed","version":"1.33.0"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V4","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","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"MODERATE"}],"references":["https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-p9f8-wvj8-2fg8","https://nvd.nist.gov/vuln/detail/CVE-2026-81869","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","https://github.com/open-telemetry/opentelemetry-go/releases/tag/sdk/v1.33.0"],"sourceUrl":"https://github.com/advisories/GHSA-p9f8-wvj8-2fg8","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-p9f8-wvj8-2fg8","identifiers":["GHSA-p9f8-wvj8-2fg8","CVE-2026-81869","GO-2026-6616"]},"retained":false,"historicalAffected":[]},{"revision":"54c85c4bd3e34b89bad58f0f6721da9d","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GO-2026-6616","aliases":["CVE-2026-81869","GHSA-p9f8-wvj8-2fg8"],"title":"OpenTelemetry-Go: UTF-8 replacement rune bypasses attribute length truncation in go.opentelemetry.io/otel/sdk","description":"OpenTelemetry-Go: UTF-8 replacement rune bypasses attribute length truncation in go.opentelemetry.io/otel/sdk","state":0,"publishedAt":"2026-10-01T20:24:10+00:00","modifiedAt":"2026-10-01T20:45:17.2241669+00:00","affected":[{"ecosystem":"Go","name":"go.opentelemetry.io/otel/sdk","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"1.10.0"},{"kind":"fixed","version":"1.33.0"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[],"references":["https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-p9f8-wvj8-2fg8","https://github.com/open-telemetry/opentelemetry-go/commit/e016a78c9f5b24a1c2beeaad47686c2f2213f49a","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/releases/tag/sdk/v1.33.0"],"sourceUrl":"https://osv.dev/vulnerability/GO-2026-6616","license":"OSV · upstream source license applies","key":"osv:GO-2026-6616","identifiers":["GO-2026-6616","CVE-2026-81869","GHSA-p9f8-wvj8-2fg8"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. Missing entries do not establish absence of exploitation.","generation":"2026-11-11T21:58:49.5594544+00:00","complete":true,"records":1779,"lastAttemptAt":"2026-11-11T21:58:49.5594544+00:00","lastSuccessAt":"2026-11-11T21:58:49.7696899+00:00","error":null,"lastVerifiedAt":"2026-11-11T21:58:49.7696907+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"cve-program","scope":"Official CVE Program baseline and cumulative hourly delta; all vendors, published and rejected records","generation":"cve-de3b77103708811b6494d2ff7c979037d73ae579742cd1649a5c765137ae5083-0cd050aa4e3407be88a99da87c4684cdd6e2bb2192e7b5d8516c5221fe2996c0","complete":true,"records":424321,"lastAttemptAt":"2026-11-11T21:56:53.6118096+00:00","lastSuccessAt":"2026-11-11T21:56:53.4062549+00:00","error":null,"lastVerifiedAt":"2026-11-11T21:56:53.6118096+00:00","snapshotPublishedAt":"2026-11-11T21:25:28+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"euvd","scope":"Rolling EUVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. 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