CVE-2016-6581

Published Jan 10, 2017 CVSS 3.0 · 7.5 High EPSS 1.9% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
EUVD EUVD EUVD-2017-0059 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.
Github GHSA Github GHSA GHSA-ffq8-576r-v26g HPACK Denial of Service vulnerability (HPACK Bomb)
History

No history.

Weaknesses

Sources

Status
PUBLISHED
Assigner
mitre
Published
Updated
Aug 6, 2024, 1:36 AM
Reserved
Aug 3, 2016, 12:00 AM
Status
Modified
Published
Jan 10, 2017, 3:59 PM
Modified
Jun 17, 2026, 12:51 AM