CVE-2016-6581 — HIGH (7.5) — White Hats Nepal

Vulnerability 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.

CVSS Score

7.5

HIGH

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

NONE

Integrity

NONE

Availability

HIGH

Affected Products

Vendor	Product	Versions
Python	Hpack	1.0
Python	Hyper	0.4

Related Weaknesses (CWE)

CWE-399

References

http://www.securityfocus.com/bid/92315Third Party AdvisoryVDB Entry
https://python-hyper.org/hpack/en/latest/security/CVE-2016-6581.htmlMitigationVendor Advisory
http://www.securityfocus.com/bid/92315Third Party AdvisoryVDB Entry
https://python-hyper.org/hpack/en/latest/security/CVE-2016-6581.htmlMitigationVendor Advisory

FAQ

What is CVE-2016-6581?

CVE-2016-6581 is a vulnerability with a CVSS score of 7.5 (HIGH). 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. Th...

How severe is CVE-2016-6581?

CVE-2016-6581 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2016-6581?

Check the references section above for vendor advisories and patch information. Affected products include: Python Hpack, Python Hyper.