vulnerability / NVI-00013254 / Revision 3
OpenTelemetry-Go: UTF-8 replacement rune bypasses attribute length truncation
GitHub lists this reviewed advisory for go.opentelemetry.io/otel/sdk. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
5.1 MEDIUM (4.0)
security-advisories@github.com severity; no combined Null risk score.
0.180%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.07631. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
go.opentelemetry.io/otel/sdk
source listed>= 1.10.0, < 1.33.0
### Summary The 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. Introduced in commit 49a6536 ### Details String 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`. `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` t
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
- NVD lastModified does not establish freshness of every associated CPE record.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-p9f8-wvj8-2fg8 ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- CVE-2026-81869 ↗
NIST National Vulnerability Database · official catalog
Observed . This product uses data from the NVD API but is not endorsed or certified by the NVD.
- CVE-2026-81869 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 3 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.