CVE-2023-21839 Oracle WebLogic Server Unspecified

Exploited in the wild High 7.5 Published 17 Jan 2023 Updated 21 Oct 2025

Unauthenticated attackers can exploit deserialization flaws in Oracle WebLogic Server to access critical data via T3 or IIOP protocols.

Exploited in the wild: Since 1 May 2023
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2023-21839?

CVE-2023-21839 is a high-severity unsafe deserialization vulnerability in Oracle Weblogic Server, published on 17 Jan 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Vulnerability in the Oracle WebLogic Server product of Oracle Fusion Middleware (component: Core). Supported versions that are affected are 12.2.1.3.0, 12.2.1.4.0 and 14.1.1.0.0. Easily exploitable vulnerability allows unauthenticated attacker with network access via T3, IIOP to compromise Oracle WebLogic Server. Successful attacks of this vulnerability can result in unauthorized access to critical data or complete access to all Oracle WebLogic Server accessible data. CVSS 3.1 Base Score 7.5 (Confidentiality impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).

Weakness: CWE-502, CWE-306

Which versions are affected by CVE-2023-21839?

It affects 1 product.

Products include Oracle Weblogic Server.

How do I fix CVE-2023-21839?

No fix has been published for CVE-2023-21839 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 22 May 2023.

Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.

Is CVE-2023-21839 being exploited?

Yes. Attackers have exploited CVE-2023-21839 in the wild since at least 1 May 2023.

Public exploit code: 1 Metasploit module, 1 Nuclei template and 8 proofs of concept on GitHub.

All Oracle Weblogic Server vulnerabilities

Sources

Also known as GHSA-f8x3-c29w-wfmj.