CVE-2026-44163 fluent-plugin-opentelemetry: Denial of Service (DoS) via Large Payloads and Decompression Bombs in `in_opentelemetry`
Attackers can crash Fluentd by sending large or compressed payloads to the OpenTelemetry input plugin, disrupting log collection.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-44163?
CVE-2026-44163 is a medium-severity denial of service vulnerability in fluent-plugins-nursery fluent-plugin-opentelemetry, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
fluent-plugin-opentelemetry is a Fluentd input and output plugin for forwarding OpenTelemetry Protocol data. Prior to 0.5.3, the in_opentelemetry HTTP input read the entire incoming request body and decompressed payloads into memory without enforcing maximum size thresholds. When an OpenTelemetry ingestion endpoint was exposed to an untrusted network, an attacker could send an excessively large request or a highly compressed payload that expanded in memory. The resulting memory exhaustion could cause the operating system to terminate the Fluentd process, disrupting all log collection and forwarding on the affected node. This issue is fixed in version 0.5.3.
Weakness: CWE-409
Which versions are affected by CVE-2026-44163?
2 open source packages ship an affected version, including fluent-plugin-opentelemetry.
| Package | Affected | Fixed in |
|---|---|---|
fluent-plugin-opentelemetry RubyGems | All versions | 0.5.3 |
fluent-plugin-opentelemetry RubyGems | All versions | 0.5.3 |
How do I fix CVE-2026-44163?
Upgrade fluent-plugin-opentelemetry to 0.5.3 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-44163 being exploited?
There is no known exploitation of CVE-2026-44163 in the wild and no public exploit code.
Sources
Also known as GHSA-2jc5-xhx8-qj6h.