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Commons ConfigurationApplication · Apache

CVE-2020-1953

CRITICAL · 10.0 CVSS v3.1 Published 2020-03-13
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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
Apache Commons Configuration uses a third-party library to parse YAML files which by default allows the instantiation of classes if the YAML includes special statements. Apache Commons Configuration versions 2.2, 2.3, 2.4, 2.5, 2.6 did not change the default settings of this library. So if a YAML file was loaded from an untrusted source, it could therefore load and execute code out of the control of the host application.

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

Apache Commons Configuration versions 2.2-2.6 use the SnakeYAML library to parse YAML files without disabling unsafe deserialization. By default, SnakeYAML allows instantiation of arbitrary Java classes via special YAML tags (e.g., !!java/object/), enabling remote code execution when parsing YAML from untrusted sources.

MitigationUpgrade to Apache Commons Configuration 2.7 or later which disables unsafe deserialization by default, or configure SnakeYAML with a SafeConstructor that restricts object instantiation. Never load YAML configuration from untrusted or user-controlled sources.

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
Commons ConfigurationApplication
Affected:= 2.2= 2.3= 2.4= 2.5= 2.6
Database ServerDatabase / datastore
Affected:= 11.2.0.4= 12.1.0.2= 12.2.0.1= 18c= 19c
Healthcare FoundationApplication
Affected:= 7.1.1= 7.2.0= 7.2.1= 7.3.0

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
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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 Apache Commons Configuration version
    Search for commons-configuration*.jar in your application classpath, lib directories, or dependency manifests (pom.xml, build.gradle, etc.), and note the exact version number
    Affected if Version is 2.2, 2.3, 2.4, 2.5, or 2.6
  2. Confirm SnakeYAML is on the classpath
    Search for snakeyaml*.jar in your application classpath, lib directories, or dependency manifests
    Affected if SnakeYAML library is present alongside Apache Commons Configuration
  3. Determine if YAML configuration is being parsed
    Review application code and configuration for calls to ConfigUtils, ConfigurationBuilder, or YAML-based configuration loaders that process .yml or .yaml files
    Affected if Application loads YAML files using Apache Commons Configuration's YAML support
  4. Identify the YAML data source origin
    Trace where YAML configuration files are loaded from: file system paths, URLs, user uploads, network sources, or database records
    Affected if YAML files originate from untrusted or user-controlled sources (e.g., user uploads, external URLs, database fields)

You are affected if Apache Commons Configuration version 2.2-2.6 is in use, SnakeYAML is on the classpath, and your application parses YAML configuration files from any source, with elevated risk from untrusted inputs.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to Apache Commons Configuration 2.7 or later which disables unsafe deserialization by default, or configure SnakeYAML with a SafeConstructor that restricts object instantiation. Never load YAML configuration from untrusted or user-controlled sources.

Recommended fix High confidence

Apache Commons Configuration 2.7 or later (2.8.x, 2.9.x recommended)

  1. 1. Upgrade Apache Commons Configuration to version 2.7 or later (e.g., 2.7, 2.8, 2.9, or latest stable 2.x release)
  2. 2. Update the Maven dependency: Change version from 2.2-2.6 to 2.7 or later in pom.xml
  3. 3. Rebuild and redeploy the application
  4. 4. Test that YAML configuration files load correctly and application functionality is intact
  5. 5. If using custom YAML constructors, review them for security implications
Caveat Minimal - version 2.7 changed the default YAML loader to be secure; verify no custom YAML constructors are needed that relied on unsafe loading

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

Fix this in Commons Configuration Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,920
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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-2020-1953 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data