CVE Intelligence
Medium

CVE-2026-39882 — OpenTelemetry-Go OTLP HTTP exporters read unbounded HTTP response bodies

OpenTelemetry-Go is the Go implementation of OpenTelemetry. Prior to 1.43.0, the otlp HTTP exporters (traces/metrics/logs) read the full HTTP response body into an in-memory bytes.Buffer without a size cap. This is exploitable for memory exhaustion when the configured collector endpoint is attacker-controlled (or a network attacker can mitm the exporter connection). This vulnerability is fixed in 1.43.0.

Published Apr 8, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: GitHub_M

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.2% (30-day exploitation probability)+1
  • Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.19%
ahead of 8% of scored CVEs · Oct 14, 2026
Affects
Open-telemetry
Opentelemetry and 1 more
CVSS base
5.3
Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Documented patch — github.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Open-telemetry Opentelemetry, Open-telemetry Opentelemetry-go).
  2. Apply the fixed version or the patch documented under Remediation.
  3. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Open-telemetry Opentelemetry < 1.43.0 Vulnerable NIST National Vulnerability Database
Open-telemetry Opentelemetry-go version < 1.43.0 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Adjacent
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
5.3 CVSS 3.1 Medium 1.6 3.6 security-advisories@github.com via NIST National Vulnerability Database
5.3 CVSS 3.1 Medium — — GitHub_M via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: security-advisories@github.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-789

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.19%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Not enough vector or weakness data: use the affected application’s logs as a starting point.
application logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · open-telemetry/opentelemetry-go
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • Fix documented
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVSS changed · 5.3
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVE published
    Apr 8, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

2 on the record

Elsewhere on this site

Open-telemetry
every CVE for this vendor
CWE-789
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-45404 OpenTelemetry-Go: Unsynchronized baggage map can panic under concurrent access Aug 24, 2026
  • CVE-2026-54285 opentelemetry-js: Unbounded memory allocation in W3C Baggage propagation Jun 22, 2026
  • CVE-2026-44967 opentelemetry-cpp: OTLP HTTP exporters read unbounded HTTP response Jun 12, 2026
  • CVE-2026-41178 OpenTelemetry-Go's baggage parsing no longer caps raw header length Jun 4, 2026
  • CVE-2026-40894 OpenTelemetry dotnet: Excessive memory allocation when parsing OpenTelemetry propagation headers Apr 23, 2026
  • CVE-2026-41078 OpenTelemetry dotnet: Potential memory exhaustion via unbounded pooled-list sizing in Jaeger exporter conversion path Apr 23, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-39882 is "OpenTelemetry-Go OTLP HTTP exporters read unbounded HTTP response bodies", rated Medium. It affects Opentelemetry (Open-telemetry); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.3 describes technical severity. EPSS 0.19% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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