CVE-2026-81869

MEDIUMPre-NVD 5.15.1—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 97% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this weekElevated
5.1EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.1Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
5.1
EG Score
5.1(medium)
EG Risk
39(Track)
EG Risk 39/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity51% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
3%
KEV
Not listed

Published

September 16, 2026

Last Modified

September 17, 2026

Advisory Details (4)

Auto-updated Sep 16, 2026
🔬 Proof of concept available. Patch available. Sources: github_pr, github_commit, github.
github_commit

commit e016a78c9f5b (open-telemetry/opentelemetry-go)

Fix landed in open-telemetry/opentelemetry-go commit e016a78c9f5b — awaiting tagged release

https://github.com/open-telemetry/opentelemetry-go/commit/e016a78c9f5b24a1c2beeaad47686c2f2213f49a
github_pr

Fix attribute value truncation

Fix merged in open-telemetry/opentelemetry-go PR #5997 on 2024-11-26 — awaiting tagged release

https://github.com/open-telemetry/opentelemetry-go/pull/5997
generic

Span attributes are truncated by number of bytes not number of characters · Issue #5996 · open-telemetry/opentelemetry-go · GitHub

https://github.com/open-telemetry/opentelemetry-go/issues/5996
github Patch Available🟡 PoC Available

UTF-8 replacement rune bypasses attribute length truncation · Advisory · open-telemetry/opentelemetry-go · GitHub

https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-p9f8-wvj8-2fg8

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 7× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-18 17:14 UTCEG score recompute
  3. 2026-09-17 15:24 UTCEG score recompute
  4. 2026-09-17 14:35 UTCEG score recompute
  5. 2026-09-16 21:23 UTCEG score recompute
  6. 2026-09-16 20:46 UTCEG score recompute
  7. 2026-09-16 20:44 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-81869?
CVE-2026-81869 is a medium vulnerability published on September 16, 2026. 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.…
When was CVE-2026-81869 disclosed?
CVE-2026-81869 was first published in the National Vulnerability Database on September 16, 2026, with the most recent update on September 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-81869 actively exploited?
CVE-2026-81869 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 97.3% of all scored CVEs.
What is the CVSS score of CVE-2026-81869?
CVE-2026-81869 has a CVSS v3 base score of 5.1 (NVD).
How do I remediate CVE-2026-81869?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-81869, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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