CVE-2026-128085

opentelemetry-go: AttributeValueLengthLimit is fully bypassed by attribute values composed of valid U+FFFD runes

publishedCWE-135CWE-770

OpenTelemetry-Go is the Go implementation of OpenTelemetry. From SDK version 1.33.0, SDK log version 0.9.0, and trace version 1.35.0 until version 1.47.0, the AttributeValueLengthLimit and WithAttributeValueLengthLimit truncation paths in sdk/internal/attrnorm, sdk/log/internal/attrnorm, and trace/auto.go do not count valid U+FFFD replacement characters. This is a distinct incomplete-fix defect in the replacement truncation code introduced by the remediation for CVE-2026-81869. Values composed of or dominated by those characters can therefore exceed the configured character and memory bound in span, log-record, and auto-instrumentation trace attributes. Attacker-controlled telemetry attributes can increase retained memory and pipeline pressure, while confidentiality and integrity are not affected. This issue is fixed in version 1.47.0.

Technical severity5.3 mediumCVSS 3.1 · CNA: GitHub_M

Published2026-11-13Source updated 2026-11-13

Collected2026-11-132 attributed sources

Fixes and workarounds

Fix

go.opentelemetry.io/otel/sdk (Go): OSV reports a fixed version 1.47.0. Check the advisory for supported release branches.

Source: OSV GHSA-q7gw-24fr-5p69

Fix

go.opentelemetry.io/otel/sdk/log (Go): OSV reports a fixed version 1.47.0. Check the advisory for supported release branches.

Source: OSV GHSA-q7gw-24fr-5p69

Fix

go.opentelemetry.io/otel/trace (Go): OSV reports a fixed version 1.47.0. Check the advisory for supported release branches.

Source: OSV GHSA-q7gw-24fr-5p69

Affected products and versions

Affected products, source version ranges and reporting authorities
Product	Versions	Authority
opentelemetry-go open-telemetry	>= 0.9.0, < 1.47.0 (affected)	CNA: GitHub_M
go.opentelemetry.io/otel/sdk open-telemetry	>= 1.33.0, < 1.47.0 (affected)	CNA: GitHub_M
go.opentelemetry.io/otel/sdk open-telemetry	>= 0.9.0, < 1.47.0 (affected)	CNA: GitHub_M
go.opentelemetry.io/otel/sdk open-telemetry	>= 1.35.0, < 1.47.0 (affected)	CNA: GitHub_M
go.opentelemetry.io/otel/sdk `go.opentelemetry.io/otel/sdk` Go	≥ 1.33.0; < 1.47.0 (affected, semver); OSV events: introduced 1.33.0; fixed 1.47.0 Source events (semver) `[ { "introduced": "1.33.0" }, { "fixed": "1.47.0" } ]` Other versions: unaffected	OSV GHSA-q7gw-24fr-5p69
go.opentelemetry.io/otel/sdk/log `go.opentelemetry.io/otel/sdk/log` Go	≥ 0.9.0; < 1.47.0 (affected, semver); OSV events: introduced 0.9.0; fixed 1.47.0 Source events (semver) `[ { "introduced": "0.9.0" }, { "fixed": "1.47.0" } ]` Other versions: unaffected	OSV GHSA-q7gw-24fr-5p69
go.opentelemetry.io/otel/trace `go.opentelemetry.io/otel/trace` Go	≥ 1.35.0; < 1.47.0 (affected, semver); OSV events: introduced 1.35.0; fixed 1.47.0 Source events (semver) `[ { "introduced": "1.35.0" }, { "fixed": "1.47.0" } ]` Other versions: unaffected	OSV GHSA-q7gw-24fr-5p69

Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.

CVSS assessments

CVSS scores, vectors and reporting authorities
Version / score	Vector	Authority
3.1 / 5.3 medium	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`	CNA: GitHub_M

Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

References

https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-q7gw-24fr-5p69CNA: GitHub_M · x_refsource_CONFIRM
https://github.com/open-telemetry/opentelemetry-go/commit/017b08c7f1018b619991aaf6b2299d4beb9da1d3CNA: GitHub_M · x_refsource_MISC
https://github.com/open-telemetry/opentelemetry-go/releases/tag/sdk/log/v1.47.0CNA: GitHub_M · x_refsource_MISC
https://github.com/open-telemetry/opentelemetry-go/releases/tag/sdk/v1.47.0CNA: GitHub_M · x_refsource_MISC
https://github.com/open-telemetry/opentelemetry-go/releases/tag/trace/v1.47.0CNA: GitHub_M · x_refsource_MISC
https://github.com/advisories/GHSA-q7gw-24fr-5p69OSV / GitHub Security Advisories · advisory
https://osv.dev/vulnerability/GHSA-q7gw-24fr-5p69OSV / GitHub Security Advisories · osv

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