Security Bulletin: CVE-2019-17638 jetty double-release of a byte buffer

Summary

In Eclipse Jetty, versions 9.4.27.v20200227 to 9.4.29.v20200521, in case of too large response headers, Jetty throws an exception to produce an HTTP 431 error. When this happens, the ByteBuffer containing the HTTP response headers is released back to the ByteBufferPool twice. Because of this double release, two threads can acquire the same ByteBuffer from the pool and while thread1 is about to use the ByteBuffer to write response1 data, thread2 fills the ByteBuffer with other data. Thread1 then proceeds to write the buffer that now contains different data. This results in client1, which issued request1 seeing data from another request or response which could contain sensitive data belonging to client2 (HTTP session ids, authentication credentials, etc.).

Vulnerability Details

CVEID:CVE-2019-17638
**DESCRIPTION:**Eclipse Jetty, as bundled in Jenkins, could allow a remote attacker to obtain sensitive information, caused by an issue with corrupt HTTP response buffer being sent to different clients. By sending a specially-crafted HTTP request, an attacker could exploit this vulnerability to obtain sensitive information, and use this information to launch further attacks against the affected system.
CVSS Base score: 9.4
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/185436 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L)

Affected Products and Versions

Remediation/Fixes

Upgrade to 6.2.7.9, 7.0.5.4, 7.1.1.0 or later.

• https://www.ibm.com/support/fixcentral/swg/doSelectFixes?options.selectedFixes=6.2.7.9-IBM-UrbanCode-Deploy&continue=1
• https://www.ibm.com/support/fixcentral/swg/doSelectFixes?options.selectedFixes=7.0.5.4-IBM-UrbanCode-Deploy&continue=1
• https://www.ibm.com/support/fixcentral/swg/doSelectFixes?options.selectedFixes=7.1.1.0.ifix01-IBM-UrbanCode-Deploy&continue=1

Workarounds and Mitigations

None