What is CVE-2023-21839?

CVE-2023-21839 is a high-severity vulnerability in Oracle Weblogic Server, classified under Deserialization of Untrusted Data. CVSS score: 7.5/10. Published 2023-01-18.

How severe is CVE-2023-21839?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2023-21839 known to be exploited?

Yes. CVE-2023-21839 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2023-05-01), indicating it is being actively exploited. 68 public proof-of-concept repositories are indexed.

Auth bypass in Oracle Weblogic Server

CVE-2023-21839

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).

Vulnerability class: Insecure Deserialization

Published 2023-01-18 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.999 (100.0th percentile), scored 2026-10-12.

Very high probability of exploitation in the next 30 days — among the top 0.1% most-likely-to-be-exploited CVEs. 100th percentile — 100.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

The 30-day trend appears once there are two daily scores.

Affected products

Oracle Weblogic Server — versions 12.2.1.3.0, 12.2.1.4.0, 14.1.1.0.0
Oracle Corporation Weblogic Server — versions 12.2.1.3.0, 12.2.1.4.0, 14.1.1.0.0

Weakness classification (CWE)

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2023-05-01. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2023-05-22.

Required action: Apply updates per vendor instructions.

Public proof-of-concept exploits

References

www.oracle.com/security-alerts/cpujan2023.html (vendor-advisory, Patch, Vendor Advisory)
packetstormsecurity.com/files/172882/Oracle-Weblogic-PreAuth-Remote-Command-Exe… (Exploit, VDB Entry, Third Party Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2023-21839?: CVE-2023-21839 is a high-severity vulnerability in Oracle Weblogic Server, classified under Deserialization of Untrusted Data. CVSS score: 7.5/10. Published 2023-01-18.
How severe is CVE-2023-21839?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2023-21839 known to be exploited?: Yes. CVE-2023-21839 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2023-05-01), indicating it is being actively exploited. 68 public proof-of-concept repositories are indexed.