Package Instance

Jetty vulnerable to Invalid HTTP/2 requests that can lead to denial of service
### Description
Invalid HTTP/2 requests (for example, invalid URIs) are incorrectly handled by writing a blocking error response directly from the selector thread.
If the client manages to exhaust the HTTP/2 flow control window, or TCP congest the connection, the selector thread will be blocked trying to write the error response.
If this is repeated for all the selector threads, the server becomes unresponsive, causing the denial of service.

### Impact
A malicious client may render the server unresponsive.

### Patches
The fix is available in Jetty versions 9.4.47. 10.0.10, 11.0.10.

### Workarounds
No workaround available within Jetty itself.
One possible workaround is to filter the requests before sending them to Jetty (for example in a proxy)

### For more information
If you have any questions or comments about this advisory:
* Email us at security@webtide.com.

Observable timing discrepancy allows determining username validity in Jenkins
In Jenkins 2.355 and earlier, LTS 2.332.3 and earlier, an observable timing discrepancy on the login form allows distinguishing between login attempts with an invalid username, and login attempts with a valid username and wrong password, when using the Jenkins user database security realm. This allows attackers to determine the validity of attacker-specified usernames.

Login attempts with an invalid username now validate a synthetic password to eliminate the timing discrepancy in Jenkins 2.356, LTS 2.332.4.