There are 3 open security issues in buster.
3 issues left for the package maintainer to handle:
It was found that in icedtea-web up to and including 1.7.2 and 1.8.2 executable code could be injected in a JAR file without compromising the signature verification. An attacker could use this flaw to inject code in a trusted JAR. The code would be executed inside the sandbox.
It was found that icedtea-web though 1.7.2 and 1.8.2 did not properly sanitize paths from <jar/> elements in JNLP files. An attacker could trick a victim into running a specially crafted application and use this flaw to upload arbitrary files to arbitrary locations in the context of the user.
It was found that icedtea-web up to and including 1.7.2 and 1.8.2 was vulnerable to a zip-slip attack during auto-extraction of a JAR file. An attacker could use this flaw to write files to arbitrary locations. This could also be used to replace the main running application and, possibly, break out of the sandbox.
You can find information about how to handle these issues in the security team's documentation.