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CVE-2026-40894: OpenTelemetry dotnet is a dotnet telemetry framework

33
Routine
MEDIUM 5.3REMOTEUPGRADEUPGRADEUPGRADE

CVE-2026-40894 is a medium-severity flaw (CVSS 5.3) affecting opentelemetry, opentelemetry.api, opentelemetry.extensions.propagators. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

OpenTelemetry dotnet is a dotnet telemetry framework. In OpenTelemetry.Api 0.5.0-beta.2 to 1.15.2 and OpenTelemetry.Extensions.Propagators 1.3.1 to 1.15.2, The implementation details of the baggage, B3 and Jaeger processing code in the OpenTelemetry.Api and OpenTelemetry.Extensions.Propagators NuGet packages can allocate excessive memory when parsing which could create a potential denial of service (DoS) in the consuming application. This vulnera

Why this priority

  • Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score5.3 (Medium)
Attack vectorNetwork (remote)
Attack complexityLow
Privileges neededNone
User interactionNone
EPSS exploit chance0.5% (top 61%)
CISA exploited listNo
WeaknessCWE-789
Published2026-04-23
Last modified2026-10-26
Publisher (CNA): GitHub, Inc. · Vendor: opentelemetry

Share: LinkedIn · X · Reddit

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

Am I affected?

Timeline

opentelemetry opentelemetry UPGRADE
Affected: >= 0.5.0 and < 1.15.3
Fixed in: 1.15.3
Safe to downgrade to: a release before 0.5.0
1. Check installed version
apt-cache policy opentelemetry || rpm -q opentelemetry || opentelemetry --version
2. UPGRADE to 1.15.3 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade opentelemetry
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade opentelemetry
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 0.5.0 (Debian / Ubuntu)
apt-cache madison opentelemetry sudo apt install opentelemetry=<VERSION_BEFORE_0.5.0> sudo apt-mark hold opentelemetry
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list opentelemetry sudo dnf downgrade opentelemetry-<VERSION_BEFORE_0.5.0> sudo dnf versionlock add opentelemetry
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.
opentelemetry opentelemetry.api UPGRADE
Affected: >= 0.5.0 and < 1.15.3
Fixed in: 1.15.3
Safe to downgrade to: a release before 0.5.0
1. Check installed version
apt-cache policy opentelemetry.api || rpm -q opentelemetry.api || opentelemetry.api --version
2. UPGRADE to 1.15.3 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade opentelemetry.api
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade opentelemetry.api
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 0.5.0 (Debian / Ubuntu)
apt-cache madison opentelemetry.api sudo apt install opentelemetry.api=<VERSION_BEFORE_0.5.0> sudo apt-mark hold opentelemetry.api
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list opentelemetry.api sudo dnf downgrade opentelemetry.api-<VERSION_BEFORE_0.5.0> sudo dnf versionlock add opentelemetry.api
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.
opentelemetry opentelemetry.extensions.propagators UPGRADE
Affected: > 1.3.0 and < 1.15.3
Fixed in: 1.15.3
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy opentelemetry.extensions.propagators || rpm -q opentelemetry.extensions.propagators || opentelemetry.extensions.propagators --version
2. UPGRADE to 1.15.3 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade opentelemetry.extensions.propagators
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade opentelemetry.extensions.propagators
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
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-2026-40894?

opentelemetry: upgrade to 1.15.3; opentelemetry.api: upgrade to 1.15.3; opentelemetry.extensions.propagators: upgrade to 1.15.3. Exact commands for each OS are on this page.

Is CVE-2026-40894 being exploited?

CVE-2026-40894 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-2026-40894 affect?

CVE-2026-40894 affects opentelemetry, opentelemetry.api, opentelemetry.extensions.propagators. Severity is medium (CVSS 5.3). OpenTelemetry dotnet is a dotnet telemetry framework. In OpenTelemetry.Api 0.5.0-beta.2 to 1.15.2 and OpenTelemetry.Extensions.Propagators 1.3.1 to 1.15.2, The implementation details of the baggage, B3 and Jaeger processing code in the Open

How urgent is CVE-2026-40894?

Priority 33/100. Remotely exploitable, no login, no user action

Related CVEs

References

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