CVE-2016-6581 - CVE House
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Status published High CVE-2016-6581

A HTTP/2 implementation built using any version of the Python...

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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

References

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Affected Vendor

Affected Software

hpack, hyper
Vulnerable Versions:
1.0, 2.0, 2.0.1, 2.1.1, 2.2, 0.4, 0.6

Timeline

Official Publish: January 10th, 2017
Last Modified: August 6th, 2024
Added to House: July 20th, 2026

CVSS Vectors

V3: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weaknesses (CWE)

No CWE data available

MITRE ATT&CK TTPs

No associated TTPs found for this vulnerability.