CVE-2023-37475: Attacker-controlled parameter can cause denial of service in hamba avro

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2023-07-17 · updated 2026-06-17
Weakness: CWE-400

Description

Hamba avro is a go lang encoder/decoder implementation of the avro codec specification. In affected versions a well-crafted string passed to avro's `github.com/hamba/avro/v2.Unmarshal()` can throw a `fatal error: runtime: out of memory` which is unrecoverable and can cause denial of service of the consumer of avro. The root cause of the issue is that avro uses part of the input to `Unmarshal()` to determine the size when creating a new slice and hence an attacker may consume arbitrary amounts of memory which in turn may cause the application to crash. This issue has been addressed in commit `b4a402f4` which has been included in release version `2.13.0`. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Affected products

hamba avro: before 2.13.0 — fixed in 2.13.0

How to fix

Upgrade to a fixed version: hamba avro 2.13.0. Check the vendor advisory for mitigations.

References

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