CVE-2024-20921: Oracle Java SE JDK and JRE · Difficult to exploit vulnerability allows unauthenticated attacker with network access via multiple
Affects Oracle Java SE JDK and JRESource CVE Database V5
Not known to be exploited · CVSS 5.9 Medium.
Data as of 26 Oct 2026, 08:30 UTC
- EPSS
- 0.8% chance of exploitation in 30 days – higher than 58% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 17 Feb 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
European organizations should immediately inventory and identify all systems running the affected versions of Oracle Java SE and GraalVM. Since no patches are currently listed, organizations should implement compensating controls such as restricting network access to Java-based services and APIs to trusted internal networks only, using firewalls and network segmentation. Disable or limit the use of Java Web Start and sandboxed applets that load untrusted code, or migrate to more secure application delivery methods. Employ strict input validation and API access controls to reduce attack surface. Monitor network traffic and logs for unusual access patterns to Java services. Plan for timely application of vendor patches once released. Additionally, consider deploying runtime application self-protection (RASP) or endpoint detection and response (EDR) solutions to detect and block exploitation attempts. Regularly update Java runtime environments to supported, patched versions and educate developers and administrators about secure Java deployment practices.
Description
Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: Hotspot). Supported versions that are affected are Oracle Java SE: 8u391, 8u391-perf, 11.0.21, 17.0.9, 21.0.1; Oracle GraalVM for JDK: 17.0.9, 21.0.1; Oracle GraalVM Enterprise Edition: 20.3.12, 21.3.8 and 22.3.4. Difficult to exploit vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition. Successful attacks of this vulnerability can result in unauthorized access to critical data or complete access to all Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition accessible data. Note: This vulnerability can be exploited by using APIs in the specified Component, e.g., through a web service which supplies data to the APIs. This vulnerability also applies to Java deployments, typically in clients running sandboxed Java Web Start applications or sandboxed Java applets, that load and run untrusted code (e.g., code that comes from the internet) and rely on the Java sandbox for security. CVSS 3.1 Base Score 5.9 (Confidentiality impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N).