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DubboApplication · Apache

CVE-2021-36163

CRITICAL · 9.8 CVSS v3.1 Published 2021-09-07
Fix available
A fix is available. Upgrade to after 3.0.1 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 · unedited
In Apache Dubbo, users may choose to use the Hessian protocol. The Hessian protocol is implemented on top of HTTP and passes the body of a POST request directly to a HessianSkeleton: New HessianSkeleton are created without any configuration of the serialization factory and therefore without applying the dubbo properties for applying allowed or blocked type lists. In addition, the generic service is always exposed and therefore attackers do not need to figure out a valid service/method name pair. This is fixed in 2.7.13, 2.6.10.1

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 confidence

In Apache Dubbo with the Hessian protocol enabled, HessianSkeleton instances are created without proper serialization factory configuration, bypassing the dubbo properties that enforce allowed/blocked type lists. Additionally, the generic service is exposed by default, allowing attackers to invoke arbitrary deserialization without knowing valid service/method names, leading to unauthenticated remote code execution.

MitigationUpgrade Apache Dubbo to version 2.7.13 or 2.6.10.1, or disable the Hessian protocol if not required in the deployment.

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
DubboApplication
Affected:>= 2.7.0, <= 2.7.12>= 3.0.0, <= 3.0.1

CVSS 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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the installed Apache Dubbo version
    Check your project dependencies (Maven pom.xml, Gradle build file, or JAR manifest) for the dubbo version, or query the Dubbo admin interface or runtime MBean if available
    Affected if The version falls within >= 2.7.0 and <= 2.7.12, or >= 3.0.0 and <= 3.0.1
  2. Determine if the Hessian protocol is enabled
    Review Dubbo configuration files (dubbo.properties, application.yml, or XML config) for protocol definitions. Look for entries like <dubbo:protocol name="hessian"> or dubbo.protocols.hessian in YAML
    Affected if The Hessian protocol is explicitly configured or set as the default protocol
  3. Check if the generic service exposure is enabled
    Search Dubbo configuration for <dubbo:service generic="true"> or check if the generic parameter is set to true in any service definitions, or verify if generic invocation is enabled at the provider level
    Affected if Generic service invocation is allowed or enabled on any exposed endpoint
  4. Verify if the HessianSkeleton is used without serialization factory
    Inspect the deployed Dubbo application startup logs for HessianSkeleton initialization, or review the protocol configuration to confirm no explicit serialization factory (such as HessianSerializerFactory) is configured for the Hessian protocol
    Affected if Hessian protocol is in use and no custom serialization factory is explicitly configured to enforce allowed/blocked type lists

You are affected if your Dubbo version is between 2.7.0-2.7.12 or 3.0.0-3.0.1 AND the Hessian protocol is enabled with the generic service exposed, allowing unauthenticated deserialization attacks.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to a release after 3.0.1
Interim mitigation

Upgrade Apache Dubbo to version 2.7.13 or 2.6.10.1, or disable the Hessian protocol if not required in the deployment.

Recommended fix High confidence

2.7.13 (for 2.7.x branch); 3.0.2 or later (for 3.0.x branch)

  1. Upgrade Dubbo 2.7.x to version 2.7.13 or later
  2. If using Dubbo 3.0.x, upgrade to version 3.0.2 or later (the first stable release containing the fix)
  3. After upgrading, verify that the Hessian protocol deserialization is properly secured
Caveat Review release notes for any breaking changes between your current version and the target version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Dubbo Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-36163 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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