CVE-2021-43045 Possible DOS vulnerabilities in C# Avro SDK

What is CVE-2021-43045?

CVE-2021-43045 is a high-severity denial of service vulnerability in Apache Avro, published on 6 Jan 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A vulnerability in the .NET SDK of Apache Avro allows an attacker to allocate excessive resources, potentially causing a denial-of-service attack. This issue affects .NET applications using Apache Avro version 1.10.2 and prior versions. Users should update to version 1.11.0 which addresses this issue.

Weakness: CWE-770

Which versions are affected by CVE-2021-43045?

2 open source packages ship an affected version, including Apache.Avro. It affects 1 product.

Products include Apache Avro.

How do I fix CVE-2021-43045?

Upgrade Apache.Avro to 1.11.0 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-2021-43045 being exploited?

There is no known exploitation of CVE-2021-43045 in the wild and no public exploit code.

Other vulnerabilities in Apache Avro

• CVE-2024-47561 Apache Avro Java SDK: Arbitrary Code Execution when reading Avro schema (Java SDK) Critical 9.2
• CVE-2023-39410 Apache Avro Java SDK: Memory when deserializing untrusted data in Avro Java SDK High 7.5
• CVE-2022-35724 Denial of service while reading data in Avro Rust SDK High 7.5
• CVE-2022-36124 Memory overconsumption in Avro Rust SDK High 7.5
• CVE-2022-36125 Integer overflow when reading corrupted .avro file in Avro Rust SDK High 7.5

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as CLSA-2026-1786345204, GHSA-868x-rg4c-cjqg, OESA-2023-1950.