CVE-2021-35556 Denial of service in Java SE JDK and JRE

What is CVE-2021-35556?

CVE-2021-35556 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 20 Oct 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Vulnerability in the Java SE, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: Swing). Supported versions that are affected are Java SE: 7u311, 8u301, 11.0.12, 17; Oracle GraalVM Enterprise Edition: 20.3.3 and 21.2.0. Easily exploitable vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise Java SE, Oracle GraalVM Enterprise Edition. Successful attacks of this vulnerability can result in unauthorized ability to cause a partial denial of service (partial DOS) of Java SE, Oracle GraalVM Enterprise Edition. Note: This vulnerability 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. This vulnerability does not apply to Java deployments, typically in servers, that load and run only trusted code (e.g., code installed by an administrator). CVSS 3.1 Base Score 5.3 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).

Weakness: CWE-693

Which versions are affected by CVE-2021-35556?

3 open source packages ship an affected version, including java, java-min and jre. It affects 14 products.

Products include Debian Debian Linux, Fedoraproject Fedora, Netapp Active Iq Unified Manager, Netapp E-Series Santricity Os Controller, Netapp E-Series Santricity Storage Manager, Netapp E-Series Santricity Web Services and 8 more.

How do I fix CVE-2021-35556?

Upgrade java to a fixed version for your release line: 1.7.0, 1.8.0, 7.0.321 or 8.0.311.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2021-35556 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-35556 exists.

Other vulnerabilities in Debian Debian Linux

• CVE-2015-3306 ProFTPD Improper Access Control Exploited Critical 10.0
• CVE-2025-49113 RoundCube Webmail Deserialization of Untrusted Data Exploited Critical 9.9
• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BIT-java-2021-35556, BIT-java-min-2021-35556, BIT-jre-2021-35556, CLEANSTART-2026-RD83537, CLEANSTART-2026-TM05747, DEBIAN-CVE-2021-35556 and 10 more.