CVE-2026-21933: XSS
Java SE could allow a remote attacker to bypass security controls and perform unauthorized update, insert, delete, or read operations on accessible data, caused by an easily exploitable vulnerability.
Other sources
There is a CRLF injection vulnerability in HttpServer in JDK which may lead to potential XSS.
— Red Hat
Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: Networking). Supported versions that are affected are Oracle Java SE: 8u471, 8u471-b50, 8u471-perf, 11.0.29, 17.0.17, 21.0.9, 25.0.1; Oracle GraalVM for JDK: 17.0.17 and 21.0.9; Oracle GraalVM Enterprise Edition: 21.3.16. Easily exploitable 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 require human interaction from a person other than the attacker and while the vulnerability is in Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition, attacks may significantly impact additional products (scope change). Successful attacks of this vulnerability can result in unauthorized update, insert or delete access to some of Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition accessible data as well as unauthorized read access to a subset of 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 6.1 (Confidentiality and Integrity impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N).
— NVD
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-21933?
CVE-2026-21933 is classified as a medium severity vulnerability due to its potential for causing XSS via CRLF injection.
How do I fix CVE-2026-21933?
To resolve CVE-2026-21933, update to the latest patched version of Oracle Java SE or GraalVM as recommended by Oracle.
What versions are affected by CVE-2026-21933?
Affected versions include Oracle Java SE 8u471, 11.0.29, 17.0.17, 21.0.9, and certain versions of GraalVM for JDK.
What can happen if CVE-2026-21933 is exploited?
Exploitation of CVE-2026-21933 can lead to potential XSS attacks, allowing unauthorized script execution in a user's browser.
Is CVE-2026-21933 a local or remote vulnerability?
CVE-2026-21933 is considered a remote vulnerability, as it may be exploited over the network without local access.