⚠ Reference material — not professional advice. Test in staging, back up first, verify against your specific version. Use your own judgment for your environment.
● Critical · CVSS 9.8 ⚠ ACTIVELY EXPLOITED — CISA KEV

How to Fix CVE-2020-2883: Security Vulnerability in WebLogic Server

By Sai Kiran Pandrala

⚡ At a glance
SeverityCVSS 9.8 - Critical
Actively exploited?Yes, listed in CISA KEV (added 2025-01-07)
AffectedWebLogic Server 10.3.6.0.0; WebLogic Server 12.1.3.0.0; WebLogic Server 12.2.1.3.0; WebLogic Server 12.2.1.4.0
Fixed inSee vendor advisory
Type (CWE)Not verified - see official advisory

Patch immediately. CISA added CVE-2020-2883 to the Known Exploited Vulnerabilities catalog on 2025-01-07. Federal civilian agencies must remediate by 2025-01-28. Treat every internet-reachable instance as a priority patch.

What is CVE-2020-2883?

CVE-2020-2883 is a Security Vulnerability flaw in Oracle Corporation WebLogic Server. It carries a CVSS base score of 9.8 (critical). CISA confirmed real-world exploitation by adding it to the Known Exploited Vulnerabilities catalog on 2025-01-07.

From the source record: Vulnerability in the Oracle WebLogic Server product of Oracle Fusion Middleware (component: Core). 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, T3 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).

Why it matters in practice: KEV-listed CVEs draw continuous internet-wide scanning. Any unpatched, internet-reachable installation is on borrowed time. The blast radius depends on how the affected service is exposed. An internet-facing instance with no compensating controls is the highest-risk configuration.

Am I affected?

You are affected if your installation of WebLogic Server matches a version listed in the Affected row above.

Check the Oracle product version:


# WebLogic example
. $MW_HOME/wlserver/server/bin/setWLSEnv.sh
java weblogic.version
# Java SE
java -version

How to fix CVE-2020-2883

Apply the vendor patch. Target the patched build listed on the vendor advisory. The runnable command set below covers the most common deployment patterns for WebLogic Server.

Oracle critical patch update (cpu)


# Vendor advisory: https://www.oracle.com/security-alerts/cpuapr2020.html
# Download the patch ZIP from My Oracle Support, then:
cd $ORACLE_HOME/OPatch
./opatch apply /path/to/patch_<id>
./opatch lsinventory | grep <patch_id>

After applying the patch

  1. Restart the service or device so the patched binary loads.
  2. Confirm the running version matches the Fixed in row using the verification command below.
  3. Rotate credentials and API keys that the affected service could access if the asset was exposed during the disclosure window.

If you can't patch immediately

Until the patch lands, narrow the attack surface with these runnable controls.

Reduce the attack surface

Restrict network reach to the affected service to the smallest set of hosts that must access it. On Linux:


# Vendor advisory: https://www.oracle.com/security-alerts/cpuapr2020.html
sudo iptables -A INPUT -p tcp --dport <service-port> -s 10.10.10.0/24 -j ACCEPT
sudo iptables -A INPUT -p tcp --dport <service-port> -j DROP

On Windows:


# Vendor advisory: https://www.oracle.com/security-alerts/cpuapr2020.html
New-NetFirewallRule -DisplayName "Block CVE-2020-2883 inbound" -Direction Inbound -Action Block -Protocol TCP -LocalPort <service-port>

Mitigations are temporary. Apply the vendor patch as soon as a maintenance window opens.

How to verify the fix worked

Confirm the patched build is the one actually running.

Run the product's --version or about command and compare against the Fixed in row (See vendor advisory). Re-run an authenticated vulnerability scan and confirm the scanner no longer flags CVE-2020-2883.

Also worth doing: pull recent log windows for any indicators of compromise listed in the vendor advisory, and re-run an authenticated vulnerability scan with up-to-date signatures.

Frequently asked questions

Other vulnerabilities in the same area that are worth patching alongside this one:

Is CVE-2020-2883 being exploited in the wild?

Yes. CISA added CVE-2020-2883 to the Known Exploited Vulnerabilities catalog on 2025-01-07. KEV listing means at least one confirmed real-world exploitation report exists.

Do I have to take downtime to patch?

For most Oracle Corporation WebLogic Server deployments, the patched build needs a service restart or device reboot. HA pairs and clusters can roll the upgrade by patching the standby first, failing over, then patching the former primary.

Will a WAF or IDS rule alone close CVE-2020-2883?

No. Network filters cut down opportunistic scans but they do not remove the flaw. The vendor patch is the only durable fix.

Why is CVE-2020-2883 rated critical?

The CVSS base score of 9.8 reflects network reach, low attack complexity, and high impact on confidentiality, integrity, and availability. That combination is what the rating model maps to critical.

References

*Assembled from the official vendor advisory, the NVD record, and the CISA KEV listing on 2026-05-25. Always confirm against the vendor advisory before applying changes in production.*