CVE-2016-6581

Published Jan 10, 2017

Last updated 8 years ago

Overview

Description
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.
Source
cve@mitre.org
NVD status
Analyzed

Risk scores

CVSS 3.0

Type
Primary
Base score
7.5
Impact score
3.6
Exploitability score
3.9
Vector string
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Severity
HIGH

CVSS 2.0

Type
Primary
Base score
7.8
Impact score
6.9
Exploitability score
10
Vector string
AV:N/AC:L/Au:N/C:N/I:N/A:C

Weaknesses

nvd@nist.gov
CWE-399

Social media

Hype score
Not currently trending

Configurations