How severe is CVE-2026-39882?

CVE-2026-39882 has a CVSS score of 5.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-39882?

CVE-2026-39882 affects the following packages: go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp (Go), go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp (Go), go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp (Go). Ecosystems affected: Go.

How do I fix CVE-2026-39882?

Update go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp to 1.43.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-39882 is resolved across your whole dependency graph.

How do I mitigate CVE-2026-39882 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2026-39882 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-39882 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-39882?

CVE-2026-39882 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 10th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-39882?

CVE-2026-39882 is classified as CWE-789 (CWE-789). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-39882 published, and has it been updated?

CVE-2026-39882 was published on April 8, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

CVE-2026-39882 — otlptracehttp

MEDIUMFix: open-telemetry/opentelemetry-go#8108

CVE-2026-39882 is a medium-severity (CVSS 5.3) CWE-789 vulnerability in go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp. A fix is available for go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp — see the affected versions and patch details below.

OpenTelemetry-Go OTLP HTTP exporters read unbounded HTTP response bodies

Also known asGHSA-w8rr-5gcm-pp58GO-2026-4985

Published

Apr 8, 2026

Updated

Oct 28, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-39882.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk+0.01%

Lower risk than most CVEs10th percentile — riskier than 10% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

3 pkgs affected

🐹go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp🐹go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp🐹go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

overview: this report shows that 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).

severity

HIGH

not claiming: this is a remote dos against every default deployment. claiming: if the exporter sends traces to an untrusted collector endpoint (or over a network segment where mitm is realistic), that endpoint can crash the process via a large response body.

callsite (pinned):

exporters/otlp/otlptrace/otlptracehttp/client.go:199
exporters/otlp/otlptrace/otlptracehttp/client.go:230
exporters/otlp/otlpmetric/otlpmetrichttp/client.go:170
exporters/otlp/otlpmetric/otlpmetrichttp/client.go:201
exporters/otlp/otlplog/otlploghttp/client.go:190
exporters/otlp/otlplog/otlploghttp/client.go:221

permalinks (pinned):

root cause: each exporter client reads resp.Body using io.Copy(&respData, resp.Body) into a bytes.Buffer on both success and error paths, with no upper bound.

impact: a malicious collector can force large transient heap allocations during export (peak memory scales with attacker-chosen response size) and can potentially crash the instrumented process (oom).

affected component:

go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp
go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp
go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp

repro (local-only):

unzip poc.zip -d poc
cd poc
make canonical resp_bytes=33554432 chunk_delay_ms=0

expected output contains:

[CALLSITE_HIT]: otlptracehttp.UploadTraces::io.Copy(resp.Body)
[PROOF_MARKER]: resp_bytes=33554432 peak_alloc_bytes=118050512

control (same env, patched target):

unzip poc.zip -d poc
cd poc
make control resp_bytes=33554432 chunk_delay_ms=0

expected control output contains:

[CALLSITE_HIT]: otlptracehttp.UploadTraces::io.Copy(resp.Body)
[NC_MARKER]: resp_bytes=33554432 peak_alloc_bytes=512232

attachments: poc.zip (attached)

PR_DESCRIPTION.md

attack_scenario.md

poc.zip

Fixed in: https://github.com/open-telemetry/opentelemetry-go/pull/8108

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp`	all versions	1.43.0`go get go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp@v1.43.0`
🐹Go	`go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp`	all versions	1.43.0`go get go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp@v1.43.0`
🐹Go	`go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp`	all versions	0.19.0`go get go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp@v0.19.0`

Affected Products

1 product · 1 configurations

Application

opentelemetryopentelemetry

< 1.43.0

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp to 1.43.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-39882 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This Important flaw in OpenTelemetry-Go's OTLP HTTP exporters can lead to a denial of service in Red Hat products, such as OpenShift Container Platform and Multicluster Engine for Kubernetes, that utilize OpenTelemetry-Go for telemetry collection. The vulnerability arises from the exporters reading HTTP response…

Product	Fixed in	Advisory
Red Hat OpenShift Container Platform 4.22	`openshift4/ose-thanos-rhel9:1782977513`	RHSA-2026:37585
Red Hat OpenShift Container Platform 4.22	`openshift4/ose-thanos-rhel9:1786549880`	RHSA-2026:54770

Frequently Asked Questions

overview: this report shows that 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). severity HIGH not claiming: this is a remote dos against every default deployment. claiming: if the exporter sends traces to an untrusted collector endpoint (or over a network segment where mitm is realistic), that endpoint can crash the process via a large response bo

O3 Security · Impact-Aware SCA

Is CVE-2026-39882 in your dependencies?

Find it across Go, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

5.3/10CVSS v3 base

Vector breakdown

Attack Vector

Adjacent

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Raw vector

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

CWE Classification

CWE-789CWE-789

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

Timeline

Disclosed

Apr 8, 2026

Last updated

Oct 28, 2026

Identifiers

CVE-2026-39882

GHSA-w8rr-5gcm-pp58

GO-2026-4985

References

Advisorygithub.com · CVE 2026 39882.json Advisorygithub.com · GHSA w8rr 5gcm pp58 Advisorynvd.nist.gov · CVE 2026 39882 Fixgithub.com Webgithub.com · v1.43.0 Packagegithub.com · opentelemetry go

Related vulnerabilities

Also affects otlptracehttp

This CVE is medium severity — higher than any of the other 1 CVE affecting otlptracehttp (highest there: low).

CVE-2026-81870

Same weakness: CWE-789

This CVE is medium severity; 6 of 7 other CVEs with CWE-789 are rated as high or higher (top: high).

CVE-2026-119280CVE-2026-119276CVE-2026-115907CVE-2026-115909CVE-2026-115922CVE-2026-108359CVE-2026-108106Browse all CWE-789

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 28, 2026

CVE-2026-39882 — otlptracehttp

Exploitation Status

No confirmed exploitation observed yet

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Fixing This On Your OS

Frequently Asked Questions

Is CVE-2026-39882 in your dependencies?