CVE Vulnerabilities

CVE-2016-6581

Published: Jan 10, 2017 | Modified: Jan 27, 2017
CVSS 3.x
7.5
HIGH
Source:
NVD
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.x
7.8 HIGH
AV:N/AC:L/Au:N/C:N/I:N/A:C
RedHat/V2
RedHat/V3
Ubuntu

A HTTP/2 implementation built using any version of the Python HPACK library between v1.0.0 and v2.2.0 could be targeted for a denial of service attack, specifically a so-called HPACK Bomb attack. This attack occurs when an attacker inserts a header field that is exactly the size of the HPACK dynamic header table into the dynamic header table. The attacker can then send a header block that is simply repeated requests to expand that field in the dynamic table. This can lead to a gigantic compression ratio of 4,096 or better, meaning that 16kB of data can decompress to 64MB of data on the target machine.

Affected Software

Name Vendor Start Version End Version
Hpack Python 2.1.1 2.1.1
Hyper Python 0.6 0.6
Hpack Python 2.2 2.2
Hpack Python 2.0 2.0
Hyper Python 0.4 0.4
Hpack Python 2.0.1 2.0.1
Hpack Python 1.0 1.0

References