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Log4jFramework / library · Apache

CVE-2019-17571

CRITICAL · 9.8 CVSS v3.1 Published 2019-12-20
Fix available
A fix is available. Upgrade to 4.14.3 or later.
See remediation →
100/100
Remediation priority · Urgent
High EPSS Remotely reachable No privileges Zero-click Patch available

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
Included in Log4j 1.2 is a SocketServer class that is vulnerable to deserialization of untrusted data which can be exploited to remotely execute arbitrary code when combined with a deserialization gadget when listening to untrusted network traffic for log data. This affects Log4j versions up to 1.2 up to 1.2.17.

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
How this class of weakness works · CWE-502

The application rebuilds objects from attacker-supplied serialized data, and the act of rebuilding can trigger dangerous code paths. In many runtimes this leads straight to remote code execution. The durable fix is to avoid deserializing untrusted input — or to use a strict, type-limited format with integrity checks.

General guidance for the deserialization of untrusted data class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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
Log4jFramework / library
Affected:<= 1.2.17
Debian LinuxOperating system
Affected:= 8.0= 9.0= 10.0
Ubuntu LinuxOperating system
Affected:= 18.04
BookkeeperApplication
Affected:< 4.14.3
LeapOperating system
Affected:= 15.1
Oncommand System ManagerApplication
Affected:>= 3.0, <= 3.1.3
Oncommand Workflow AutomationApplication
Affected:all versions
Application Testing SuiteApplication
Affected:= 13.3.0.1

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

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 4.14.3 or later
Fixed in 4.14.3
Vendor patch www.oracle.com →
Recommended fix High confidence

Log4j 2.x (e.g., 2.23.1) or later, or Log4j 3.x

  1. 1. Identify all applications and dependencies that use Log4j 1.2.x (up to 1.2.17) in your environment using dependency scanning tools
  2. 2. Upgrade Log4j from version 1.x to Log4j 2.x (e.g., 2.23.1 or later) or Log4j 3.x. Update the dependency in your build configuration (Maven pom.xml, Gradle build.gradle, etc.)
  3. 3. Update any code that uses Log4j 1.x API calls to use the Log4j 2.x API. Note that the package namespace changed from org.apache.log4j to org.apache.logging.log4j
  4. 4. Rebuild and test all applications that were updated to ensure logging functionality works correctly with the new API
  5. 5. If SocketServer is not needed, remove or disable any code that instantiates org.apache.log4j.net.SocketServer or similar socket-based appenders
  6. 6. Verify the fix by checking that the vulnerable SocketServer class is no longer in the classpath
Caveat API changes between Log4j 1.x and 2.x require code updates (package changed from org.apache.log4j to org.apache.logging.log4j, method signatures may differ). Thorough testing is recommended before production deployment.

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

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $3,550. Get the upgrade done

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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-2019-17571 in production — separate from our analysis above.

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What this is

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  • Version or environment caveats, and links to real fixes
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