AvroApplication · Apache
CVE-2021-43045
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA resource exhaustion vulnerability exists in the .NET SDK of Apache Avro versions 1.10.2 and prior. Attackers can exploit this by supplying specially crafted input to Avro serialization/deserialization operations, causing excessive resource allocation and potentially leading to denial of service. The vulnerability is network-exploitable with high availability impact.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
AvroApplication
< 1.11.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Apache Avro .NET SDK usageSearch your project files (*.csproj, packages.config) for 'Apache.Avro' or 'Avro' package references, or run 'dotnet list package' in your project directoryAffected if Apache Avro package is listed as a dependency
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Determine installed Avro versionCheck the version attribute in your package reference (e.g., PackageReference Include="Apache.Avro" Version="x.x.x"), or run 'dotnet list package --include-transitive' to see all package versionsAffected if Version is lower than 1.11.0 (e.g., 1.10.2, 1.10.1, 1.10.0, etc.)
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Confirm serialization/deserialization is in useSearch your codebase for calls to Avro serialization APIs such as Serialize, Deserialize, BinaryEncoder, SpecificReader, GenericRecord, or any code using Schema.Parse or JsonEncoder/JsonDecoderAffected if Your application performs Avro serialization or deserialization operations on untrusted or external input
You are affected if your project uses Apache Avro .NET SDK version below 1.11.0 and performs serialization/deserialization on external or untrusted data.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped1.11.0
Update Apache Avro .NET SDK to version 1.11.0 or later to remediate this vulnerability.
Apache Avro version 1.11.0
- 1. Identify all .NET applications in your environment that depend on Apache Avro
- 2. Check the current Avro library version in use (e.g., via project file or package manager)
- 3. Update the Apache Avro library to version 1.11.0 or later in all affected applications
- 4. Rebuild and redeploy the applications
- 5. Verify the applications function correctly after the upgrade
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Avro
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-43045 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-43045 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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