CVE-2016-6581

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Source
https://cve.org/CVERecord?id=CVE-2016-6581
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2016-6581.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2016-6581
Aliases
Downstream
Related
Published
2017-01-10T15:59:00.423Z
Modified
2026-03-14T09:21:15.645577Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
[none]
Details

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.

References

Affected packages

Git / github.com/python-hyper/hpack

Affected ranges

Type
GIT
Repo
https://github.com/python-hyper/hpack
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Last affected
fc618368a4b0c56a6bcce776787fc21cacbb5b10
Introduced
0 Unknown introduced commit / All previous commits are affected
Last affected
42ac8ce70560ae64076bcc840bd0d75d51ef8f02
Introduced
0 Unknown introduced commit / All previous commits are affected
Last affected
1258828f27a605f7efc7b84327d607e63b62bbcd
Introduced
0 Unknown introduced commit / All previous commits are affected
Last affected
89c71490c2f24a332dfd86f238caf82a2495d818
Introduced
0 Unknown introduced commit / All previous commits are affected
Last affected
ab9e9a65a6be582b33dae280b87daba269377f98
Database specific 
{
    "versions": [
        {
            "introduced": "0"
        },
        {
            "last_affected": "1.0"
        },
        {
            "introduced": "0"
        },
        {
            "last_affected": "2.0"
        },
        {
            "introduced": "0"
        },
        {
            "last_affected": "2.0.1"
        },
        {
            "introduced": "0"
        },
        {
            "last_affected": "2.1.1"
        },
        {
            "introduced": "0"
        },
        {
            "last_affected": "2.2"
        }
    ]
}

Affected versions

v1.*
v1.0.0

Database specific

unresolved_ranges 
[
    {
        "events": [
            {
                "introduced": "0"
            },
            {
                "last_affected": "0.4"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "0"
            },
            {
                "last_affected": "0.6"
            }
        ]
    }
]
source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2016-6581.json"