CVE-2016-6581
Published: 10 January 2017
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.
Priority
Status
| Package | Release | Status |
|---|---|---|
|
python-hpack Launchpad, Ubuntu, Debian |
artful |
Ignored
(end of life)
|
| bionic |
Not vulnerable
|
|
| cosmic |
Not vulnerable
|
|
| disco |
Not vulnerable
|
|
| eoan |
Not vulnerable
|
|
| focal |
Not vulnerable
|
|
| groovy |
Not vulnerable
|
|
| hirsute |
Not vulnerable
|
|
| impish |
Not vulnerable
|
|
| jammy |
Not vulnerable
|
|
| kinetic |
Not vulnerable
|
|
| lunar |
Not vulnerable
|
|
| mantic |
Not vulnerable
|
|
| precise |
Does not exist
|
|
| trusty |
Does not exist
|
|
| upstream |
Needs triage
|
|
| xenial |
Needed
|
|
| yakkety |
Ignored
(end of life)
|
|
| zesty |
Ignored
(end of life)
|
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.5 |
| Attack vector | Network |
| Attack complexity | Low |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity impact | None |
| Availability impact | High |
| Vector | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |