{"id":"GHSA-ffq8-576r-v26g","summary":"HPACK Denial of Service vulnerability (HPACK Bomb)","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.","aliases":["CVE-2016-6581","PYSEC-2017-87"],"modified":"2024-11-30T05:25:14.978140Z","published":"2019-07-05T21:11:05Z","database_specific":{"cwe_ids":[],"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2020-06-16T21:34:33Z","nvd_published_at":null},"references":[{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2016-6581"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-ffq8-576r-v26g"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/hpack/PYSEC-2017-87.yaml"},{"type":"PACKAGE","url":"https://github.com/python-hyper/hpack"},{"type":"WEB","url":"https://python-hyper.org/hpack/en/latest/security/CVE-2016-6581.html"},{"type":"WEB","url":"https://web.archive.org/web/20200227233559/http://www.securityfocus.com/bid/92315"},{"type":"WEB","url":"http://python-hyper.org/projects/hpack/en/stable/security/CVE-2016-6581.html"}],"affected":[{"package":{"name":"hpack","ecosystem":"PyPI","purl":"pkg:pypi/hpack"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.0.0"},{"fixed":"2.3.0"}]}],"versions":["1.0.0","1.0.1","1.1.0","2.0.0","2.0.1","2.1.0","2.1.1","2.2.0"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2019/07/GHSA-ffq8-576r-v26g/GHSA-ffq8-576r-v26g.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"}]}