Live › vulnerability › CVE-2026-111073
Go to dashboardThe broker's PushTelemetry API checks only the compressed size of client metrics before decompressing them with no output limit. An authenticated client can send a small, highly compressible payload that expands to hundreds of megabytes and causes OutOfMemoryError on the broker.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-28 17:34 UTC. All times on this page are UTC.
Any cluster running an affected Apache Kafka broker version is exposed, because PushTelemetry (KIP-714) is reachable by any authenticated client and is not gated by an ACL. Clusters where clients are fully trusted carry less practical risk, but an authenticated client that targets multiple brokers can affect cluster availability. Operators already on the fixed releases can skip it.
No product ranges from the sources yet.
kafka-topics.sh --version or check the Kafka version in the broker's build or package manifest, then compare against the fixed releases listed in Fix.telemetry.max.bytes is set in server.properties; the default is 1 MB, and the sources say it bounds only the compressed size on affected versions.4.2.2, 4.3.1, or 4.4.0, which enforce a decompressed size limit equal to telemetry.max.bytes and abort oversized payloads with TelemetryTooLargeException.telemetry.max.bytes is only a partial mitigation, since it reduces the worst-case expansion proportionally and does not fully prevent it.Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
The broker-side PushTelemetry API (KIP-714) validates only the compressed size of a client's metrics payload against telemetry.max.bytes (default 1 MB) before decompressing it. ClientTelemetryUtils.decompress() then decompresses the payload with no limit on the decompressed output size, growing a heap buffer until the compressed input is exhausted. A small, highly compressible payload (for example gzip-compressed zeros) can therefore expand to hundreds of megabytes of broker heap.
Impact:
An authenticated client can send a PushTelemetry request with a small compressed payload that decompresses to a very large size, consuming broker heap out of proportion to the request size. Repeated or concurrent requests can exhaust the broker heap and cause an OutOfMemoryError, degrading or crashing the broker; a client that targets multiple brokers can affect cluster availability. PushTelemetry is available to any authenticated client and is not gated by an ACL.
Mitigation:
Upgrade to Apache Kafka 4.2.2, 4.3.1, or 4.4.0. On affected versions there is no configuration that fully prevents the amplification, because telemetry.max.bytes bounds only the compressed size; lowering telemetry.max.bytes reduces the worst-case decompressed size proportionally and is a partial mitigation.
Resolution:
This page as .md · .json · in your agent: get_signal("CVE-2026-111073")
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