CVE-2026-128085 opentelemetry-go: AttributeValueLengthLimit is fully bypassed by attribute values composed of valid U+FFFD runes

5.3 mediumFix available

Medium (5.3) in open-telemetry. Fixed in go.opentelemetry.io/otel/sdk 1.47.0.

On this page

Severity
Ask an AI about this CVE
Affected
Versions
Fix and patched versions
Packages (OSV)
Attack patterns (CAPEC)
References
Your exposure

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.

Severity

CVSS 3.1

5.3 medium

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CWEs: CWE-135 Incorrect Calculation of Multi-Byte String Length
CWE-770 Allocation of Resources Without Limits or Throttling
Published: 2026-11-13 19:19 UTC
Assigned by: GitHub_M (CNA)
NVD analysis: Awaiting analysis
Record from: the NVD, synced 2026-11-13 19:41 UTC

Ask an AI about this CVE

ChatGPT Claude Google AI Mode

Show the prompt

Explain CVE-2026-128085 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-128085?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-128085?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-128085 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.

Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.

Badge for a README or a site

An image that stays current: it is drawn from the data each time it is fetched (a host that proxies images, as GitHub does, may show its copy for a while). Markdown:

[![CVE-2026-128085](https://cve.bz/cve/badge/CVE-2026-128085.svg)](https://cve.bz/cve/CVE-2026-128085)

HTML:

<a href="https://cve.bz/cve/CVE-2026-128085"><img src="https://cve.bz/cve/badge/CVE-2026-128085.svg" alt="CVE-2026-128085"></a>

Affected

open-telemetry:go.opentelemetry.io/otel/sdk
open-telemetry:opentelemetry-go

Versions

From the CNA's record in the CVE List.

Product	Affected
open-telemetry opentelemetry-go	>= 0.9.0, < 1.47.0
open-telemetry go.opentelemetry.io/otel/sdk	>= 1.33.0, < 1.47.0
open-telemetry go.opentelemetry.io/otel/sdk	>= 0.9.0, < 1.47.0
open-telemetry go.opentelemetry.io/otel/sdk	>= 1.35.0, < 1.47.0

Fix and patched versions

go.opentelemetry.io/otel/sdk (Go): fixed in 1.47.0
go.opentelemetry.io/otel/sdk/log (Go): fixed in 1.47.0
go.opentelemetry.io/otel/trace (Go): fixed in 1.47.0

Packages (OSV)

Advisory	Ecosystem	Package	Affected	Fixed in
GHSA-q7gw-24fr-5p69	Go	go.opentelemetry.io/otel/sdk	>=1.33.0 <1.47.0	1.47.0
GHSA-q7gw-24fr-5p69	Go	go.opentelemetry.io/otel/sdk/log	>=0.9.0 <1.47.0	1.47.0
GHSA-q7gw-24fr-5p69	Go	go.opentelemetry.io/otel/trace	>=1.35.0 <1.47.0	1.47.0

Attack patterns (CAPEC)

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits. More on the page of CWE-770 (20).

References

Check your stack JSON