CVE-2020-2551Known exploitationPublic exploitNetwork attack vector

Unauthenticated code execution via IIOP deserialization

Published Jan 15, 2020 · Updated Jan 12, 2026

Insecure deserialization in Oracle WebLogic Server allows remote attackers to execute arbitrary code through exposed IIOP services. The IIOP handler deserializes an attacker-supplied byte stream and inadequately filters JtaTransactionManager, enabling a malicious JNDI lookup. The attack requires no credentials or user interaction and affects 10.3.6.0.0, 12.1.3.0.0, 12.2.1.3.0, and 12.2.1.4.0 when IIOP is reachable.

CVSS severity9.8
Critical
EPSS probability93.17%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insecure deserialization in Oracle WebLogic Server allows remote attackers to execute arbitrary code through exposed IIOP services. The IIOP handler deserializes an attacker-supplied byte stream and inadequately filters JtaTransactionManager, enabling a malicious JNDI lookup. The attack requires no credentials or user interaction and affects 10.3.6.0.0, 12.1.3.0.0, 12.2.1.3.0, and 12.2.1.4.0 when IIOP is reachable.

The record

CVE
CVE-2020-2551
Published
Jan 15, 2020
Updated
Jan 12, 2026
Vendor
Oracle Corporation
Product
Oracle WebLogic Server
Classifications
T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 15, 2020CVE publishedPublication date reported by the CVE source.
  2. Jan 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.3.6.0.0
  2. Affected versionversion=12.1.3.0.0
  3. Affected versionversion=12.2.1.3.0
  4. Affected versionversion=12.2.1.4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Oracle Corporation · Oracle WebLogic Serverversion=10.3.6.0.0; version=12.1.3.0.0; version=12.2.1.3.0; version=12.2.1.4.0

Published CVSS scores

9.8Oracle CorporationCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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