Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 7 Dec 2023.
Weblogic ServerApplication · Oracle

CVE-2020-2551

CRITICAL · 9.8 CVSS v3.1 Published 2020-01-15
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
100/100
Remediation priority · Urgent
In the wild 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
Vulnerability in the Oracle WebLogic Server product of Oracle Fusion Middleware (component: WLS Core Components). Supported versions that are affected are 10.3.6.0.0, 12.1.3.0.0, 12.2.1.3.0 and 12.2.1.4.0. Easily exploitable vulnerability allows unauthenticated attacker with network access via IIOP to compromise Oracle WebLogic Server. Successful attacks of this vulnerability can result in takeover of Oracle WebLogic Server. CVSS 3.0 Base Score 9.8 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

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

Critical deserialization vulnerability in Oracle WebLogic Server's IIOP (Internet Inter-ORB Protocol) implementation allows unauthenticated remote attackers to execute arbitrary code by sending specially crafted IIOP requests, leading to complete server takeover.

MitigationApply Oracle Critical Patch Update (CPU) patches for CVE-2020-2551 or upgrade to a patched version of WebLogic Server; if patching is not immediately possible, consider disabling IIOP protocol or restricting network access to the IIOP port.

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
Weblogic ServerApplication
Affected:= 10.3.6.0.0= 12.1.3.0.0= 12.2.1.3.0= 12.2.1.4.0

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
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 WebLogic Server installation and version
    Locate the WebLogic installation directory (typically under Oracle middleware home). Check for version information in the product registry or version.txt file. Common paths include $ORACLE_HOME/wlserver_*/registry.xml or the installation inventory files.
    Affected if The installed version matches 10.3.6.0.0, 12.1.3.0.0, 12.2.1.3.0, or 12.2.1.4.0, or falls within the range 10.3.6.0.0 through 12.2.1.4.0.
  2. Verify IIOP protocol is enabled
    Inspect the WebLogic config.xml file (located in the domain config directory) for IIOP-related configuration. Look for <iiop> or <iiop-service> elements. Alternatively, log into the WebLogic Administration Console and navigate to the Server configuration to check if IIOP is enabled.
    Affected if IIOP protocol is enabled on any managed server or the administration server in the domain.
  3. Confirm IIOP listener ports are active
    Identify configured IIOP ports (default is typically the managed server port plus offset, or port 7001 for admin server). Use netstat or ss commands to check if these ports are in LISTEN state. Common WebLogic IIOP ports include 7001 (default admin), 7002 (secure admin), and managed server ports.
    Affected if The IIOP ports are open and listening, making the service reachable over the network.
  4. Check network exposure of IIOP endpoints
    Review firewall rules, network ACLs, or load balancer configurations to determine if IIOP ports are accessible from untrusted networks. Verify whether the WebLogic servers with IIOP enabled are bound to external interfaces or are exposed to the internet.
    Affected if IIOP endpoints are reachable from outside the trusted internal network or from untrusted IP addresses.

A system is affected if it runs a vulnerable WebLogic Server version (10.3.6.0.0 through 12.2.1.4.0) AND has IIOP protocol enabled AND the IIOP service is network-accessible, allowing unauthenticated remote code execution.

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
Patch available Apply the vendor patch
Vendor patch www.oracle.com →
Interim mitigation

Apply Oracle Critical Patch Update (CPU) patches for CVE-2020-2551 or upgrade to a patched version of WebLogic Server; if patching is not immediately possible, consider disabling IIOP protocol or restricting network access to the IIOP port.

Recommended fix High confidence

Upgrade to WebLogic 12.2.1.4.4+ (or latest 14.1.1.x), or apply January 2020 CPU patch to affected versions

  1. 1. Identify the currently installed WebLogic Server version using the WebLogic Administration Console or by checking the inventory.
  2. 2. Plan an upgrade to a patched version that addresses CVE-2020-2551.
  3. 3. For WebLogic 12.2.1.x, upgrade to version 12.2.1.4.4 or later, which includes the January 2020 Critical Patch Update addressing this vulnerability.
  4. 4. For WebLogic 12.2.1.3.0, apply the January 2020 CPU (Patch 30658980) or upgrade to 12.2.1.3.14 or later.
  5. 5. For WebLogic 12.1.3.0.0, apply the January 2020 CPU or upgrade to 12.1.3.0.7 or later.
  6. 6. For WebLogic 10.3.6.0.0, apply the January 2020 CPU or upgrade to 10.3.6.0.19 or later.
  7. 7. As an alternative mitigation if patching is not immediately possible, disable the IIOP protocol in the WebLogic Server administration console under: Domain > Configuration > General > Enable IIOP (uncheck).
  8. 8. If IIOP is required, restrict network access to the IIOP port (7001/7002) using firewall rules or network segmentation to limit exposure to trusted networks only.
Caveat Patches are generally additive; however, always test in a non-production environment first as some patches may require configuration adjustments or have compatibility implications with existing applications

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

Fix this in Weblogic Server Exploited in the wild — priority engagement
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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-2020-2551 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
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  • Version or environment caveats, and links to real fixes
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