CVE-2026-42191: OpenTelemetry.Exporter.OpenTelemetryProtocol is the OTLP (OpenTelemetry Protocol) exporter implementation

Routine

MEDIUM 6.5UPGRADE

CVE-2026-42191 is a medium-severity flaw (CVSS 6.5) affecting opentelemetry.exporter.opentelemetryprotocol. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

OpenTelemetry.Exporter.OpenTelemetryProtocol is the OTLP (OpenTelemetry Protocol) exporter implementation. From 1.8.0 to 1.15.2, the OTLP disk retry feature in OpenTelemetry.Exporter.OpenTelemetryProtocol silently fell back to Path.GetTempPath() when OTEL_DOTNET_EXPERIMENTAL_OTLP_RETRY=disk was set but OTEL_DOTNET_EXPERIMENTAL_OTLP_DISK_RETRY_DIRECTORY_PATH was not configured. The exporter stored and loaded *.blob files under fixed, signal-named

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Local
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.1% (top 99%)
CISA exploited list	No
Weakness	CWE-379
Published	2026-05-12
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: opentelemetry

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-12 20:16 UTCPublished CVE record published
2026-10-26 18:10 UTCUpdated Record last modified

opentelemetry opentelemetry.exporter.opentelemetryprotocol UPGRADE

Affected: >= 1.8.0 and < 1.15.3

Fixed in: 1.15.3

Safe to downgrade to: a release before 1.8.0

1. Check installed version

apt-cache policy opentelemetry.exporter.opentelemetryprotocol || rpm -q opentelemetry.exporter.opentelemetryprotocol || opentelemetry.exporter.opentelemetryprotocol --version

2. UPGRADE to 1.15.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade opentelemetry.exporter.opentelemetryprotocol

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade opentelemetry.exporter.opentelemetryprotocol

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.8.0 (Debian / Ubuntu)

apt-cache madison opentelemetry.exporter.opentelemetryprotocol sudo apt install opentelemetry.exporter.opentelemetryprotocol=<VERSION_BEFORE_1.8.0> sudo apt-mark hold opentelemetry.exporter.opentelemetryprotocol

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list opentelemetry.exporter.opentelemetryprotocol sudo dnf downgrade opentelemetry.exporter.opentelemetryprotocol-<VERSION_BEFORE_1.8.0> sudo dnf versionlock add opentelemetry.exporter.opentelemetryprotocol

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-42191?

opentelemetry.exporter.opentelemetryprotocol: upgrade to 1.15.3. Exact commands for each OS are on this page.

Is CVE-2026-42191 being exploited?

CVE-2026-42191 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-42191 affect?

CVE-2026-42191 affects opentelemetry.exporter.opentelemetryprotocol. Severity is medium (CVSS 6.5). OpenTelemetry.Exporter.OpenTelemetryProtocol is the OTLP (OpenTelemetry Protocol) exporter implementation. From 1.8.0 to 1.15.2, the OTLP disk retry feature in OpenTelemetry.Exporter.OpenTelemetryProtocol silently fell back to Path.GetTempP

How urgent is CVE-2026-42191?

Priority 23/100. No elevated risk signals yet.

References

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