However, the server may be able to recover after the `OutOfMemoryError` and continue its service - although it may take some time. An attacker client may send a large multipart request and cause the server to throw `OutOfMemoryError`. This happens even with the default settings of `fileSizeThreshold=0` which should stream the whole part content to disk. annotated with that call `HttpServletRequest.getParameter()` or `HttpServletRequest.getParts()` may cause `OutOfMemoryError` when the client sends a multipart request with a part that has a name but no filename and very large content.
In affected versions servlets with multipart support (e.g. Jetty is a java based web server and servlet engine.
There are no known workarounds for this issue. This issue has been addressed in versions 9.4.51, 10.0.14, 11.0.14, and 12.0.0.beta0 and users are advised to upgrade. This is significant when an intermediary is enacting some policy based on cookies, so a smuggled cookie can bypass that policy yet still be seen by the Jetty server or its logging system. This has security implications because if, say, JSESSIONID is an HttpOnly cookie, and the DISPLAY_LANGUAGE cookie value is rendered on the page, an attacker can smuggle the JSESSIONID cookie into the DISPLAY_LANGUAGE cookie and thereby exfiltrate it. So, a cookie header such as: `DISPLAY_LANGUAGE="b JSESSIONID=1337 c=d"` will be parsed as one cookie, with the name DISPLAY_LANGUAGE and a value of b JSESSIONID=1337 c=d instead of 3 separate cookies.
If Jetty sees a cookie VALUE that starts with `"` (double quote), it will continue to read the cookie string until it sees a closing quote - even if a semicolon is encountered.
Nonstandard cookie parsing in Jetty may allow an attacker to smuggle cookies within other cookies, or otherwise perform unintended behavior by tampering with the cookie parsing mechanism.
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