Copyright © 2012 Red Hat, Inc. All rights reserved. Important 2026-05-29T19:58:59 github.com/hamba/avro/v2: github.com/linkedin/goavro/v2: CPU Exhaustion in Avro Decoder via Unbounded Block-Count Iteration 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CWE-835

iskorotkov/avro is a fast Go Avro codec. Prior to 2.33.0, the Avro array and map decoders looped over an attacker-controlled block-count value without checking the underlying reader's error state inside the loop body. Reader.ReadBlockHeader returns the count as a Go int, which is 64-bit on amd64 / arm64 targets — so a producer can declare a block of up to math.MaxInt64 (~9.2 × 10¹⁸) elements followed by EOF (or any truncated payload), and the decoder will attempt that many no-op iterations before propagating the error. The realistic ceiling is "indefinite until the worker is killed externally" — a single hostile payload pins a CPU core until the process is OOM-killed, deadline-cancelled, or terminated. Remote, unauthenticated denial-of-service. This vulnerability is fixed in 2.33.0.

A flaw was found in the Avro array and map decoding logic in Go Avro. The decoder failed to properly stop processing after encountering read errors while iterating over attacker-controlled block-count values, leading to excessive resource consumption. A remote unauthenticated attacker could exploit this issue using specially crafted Avro payloads causing denial of service, where the affected system's CPU is consumed indefinitely until the process is terminated.

This vulnerability affects Avro array and map decoding functionality in affected Go Avro libraries. Red Hat Product Security has assessed this issue as an Important severity vulnerability. A remote unauthenticated attacker may supply specially crafted Avro payloads containing excessively large block-count values followed by truncated or invalid data. Because the decoder continued iterating after the underlying reader entered an error state, affected applications may consume excessive CPU resources for extended periods of time, potentially leading to denial of service. The currently available analysis demonstrates CPU exhaustion and service disruption but does not demonstrate confidentiality or integrity impact. Therefore, Red Hat assessed the impact as limited to Availability (A:H). Red Hat is not aware of a practical temporary workaround that fully mitigates this issue or meets Red Hat Product Security's standards for usability, deployment, applicability, or stability. Customers are advised to apply the relevant security updates when they become available. Cryostat 4 on RHEL 9 2026-07-29T00:00:00Z RHSA-2026:48151 cryostat/cryostat-storage-rhel9:4.2.0-19 Multicluster Global Hub 1.4.5 2026-07-16T00:00:00Z RHSA-2026:41030 multicluster-globalhub/multicluster-globalhub-grafana-rhel9:1784060681 Multicluster Global Hub 1.6.5 2026-07-23T00:00:00Z RHSA-2026:44622 multicluster-globalhub/multicluster-globalhub-grafana-rhel9:1784561376 Multicluster Global Hub 1.7.0 2026-07-28T00:00:00Z RHSA-2026:47149 multicluster-globalhub/multicluster-globalhub-grafana-rhel9:1784906628 Multicluster Global Hub 1.7.0 2026-08-11T00:00:00Z RHSA-2026:53530 multicluster-globalhub/multicluster-globalhub-grafana-rhel9:1785442872 Red Hat Advanced Cluster Management for Kubernetes 2.11 2026-07-16T00:00:00Z RHSA-2026:41064 rhacm2/acm-grafana-rhel9:1783578847 Red Hat Advanced Cluster Management for Kubernetes 2.13 2026-06-28T00:00:00Z RHSA-2026:30651 rhacm2/acm-grafana-rhel9:1782383730 Red Hat Advanced Cluster Management for Kubernetes 2.16 2026-08-19T00:00:00Z RHSA-2026:57191 rhacm2/acm-grafana-rhel9:1786908968 Red Hat Advanced Cluster Management for Kubernetes 2.17 2026-08-26T00:00:00Z RHSA-2026:60386 rhacm2/acm-grafana-rhel9:1787316467 Red Hat multicluster global hub 1.5.3 2026-07-21T00:00:00Z RHSA-2026:42852 multicluster-globalhub/multicluster-globalhub-grafana-rhel9:1784562060 Red Hat Enterprise Linux 10 Not affected grafana Red Hat Enterprise Linux 8 Not affected grafana Red Hat Enterprise Linux 9 Not affected grafana Red Hat Hardened Images Affected opentelemetry-collector-contrib https://www.cve.org/CVERecord?id=CVE-2026-46385 https://nvd.nist.gov/vuln/detail/CVE-2026-46385 https://github.com/iskorotkov/avro/security/advisories/GHSA-w8j3-pq8g-8m7w