{"id":"CVE-2016-6580","aliases":["EUVD-2017-0099","GHSA-h3q4-6j7f-r24c","PYSEC-2017-93"],"status":"published","title":"priority vulnerable to denial of service","description":"A HTTP/2 implementation built using any version of the Python priority library prior to version 1.2.0 could be targeted by a malicious peer by having that peer assign priority information for every possible HTTP/2 stream ID. The priority tree would happily continue to store the priority information for each stream, and would therefore allocate unbounded amounts of memory. Attempting to actually use a tree like this would also cause extremely high CPU usage to maintain the tree.","severity":{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-08","score":0.01842,"percentile":0.7915,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-399","CWE-770"],"published":"2017-01-10T15:00:00Z","modified":"2026-10-24T10:30:52Z","fixes":[{"ecosystem":"PyPI","package":"priority","fixed_in":["1.2.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"priority","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.0"}]}]},{"source":"osv","ecosystem":"PyPI","package":"priority","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.0"}]}],"versions":["0.0.1","1.0.0","1.1.0","1.1.1"]},{"source":"osv","ecosystem":"PyPI","package":"priority","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.0"}]}],"versions":["0.0.1","1.0.0","1.1.0","1.1.1"]}],"products":[{"vendor":"python","product":"python_priority_library"}],"references":[{"url":"http://www.securityfocus.com/bid/92311","tags":["vdb-entry","x_refsource_BID","x_transferred","Third Party Advisory","VDB Entry","advisory","web"]},{"url":"https://python-hyper.org/priority/en/latest/security/CVE-2016-6580.html","tags":["x_refsource_CONFIRM","x_transferred","Mitigation","Vendor Advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2016-6580","tags":["advisory"]},{"url":"https://github.com/python-hyper/priority/commit/7d01a7dc4db83bce50f20d47caf4f37b403a3ecd","tags":["web"]},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/priority/PYSEC-2017-93.yaml","tags":["web"]},{"url":"https://web.archive.org/web/20160806004329/http://www.securityfocus.com/bid/92311","tags":["web"]},{"url":"https://github.com/advisories/GHSA-h3q4-6j7f-r24c","tags":["advisory"]},{"url":"https://github.com/python-hyper/priority","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2016-6580","description":"A HTTP/2 implementation built using any version of the Python priority library prior to version 1.2.0 could be targeted by a malicious peer by having that peer assign priority information for every possible HTTP/2 stream ID. The priority tree would happily continue to store the priority information for each stream, and would therefore allocate unbounded amounts of memory. Attempting to actually use a tree like this would also cause extremely high CPU usage to maintain the tree.","status":"published","published":"2017-01-10T15:00:00Z","modified":"2024-08-06T01:36:28.17Z","updated_at":"2026-11-02T14:33:34.815789Z"}],"euvd":[{"id":"EUVD-2017-0099","description":"A HTTP/2 implementation built using any version of the Python priority library prior to version 1.2.0 could be targeted by a malicious peer by having that peer assign priority information for every possible HTTP/2 stream ID. The priority tree would happily continue to store the priority information for each stream, and would therefore allocate unbounded amounts of memory. Attempting to actually use a tree like this would also cause extremely high CPU usage to maintain the tree.","status":"published","published":"2017-01-10T15:00:00Z","modified":"2024-08-06T01:36:28Z","updated_at":"2026-11-03T02:22:35.936009Z"}],"ghsa":[{"id":"GHSA-h3q4-6j7f-r24c","title":"priority vulnerable to denial of service","description":"A HTTP/2 implementation built using any version of the Python priority library prior to version 1.2.0 could be targeted by a malicious peer by having that peer assign priority information for every possible HTTP/2 stream ID. The priority tree would happily continue to store the priority information for each stream, and would therefore allocate unbounded amounts of memory. Attempting to actually use a tree like this would also cause extremely high CPU usage to maintain the tree.","status":"published","published":"2022-05-17T03:02:35Z","modified":"2024-08-30T23:37:26Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"},{"version":"4.0","score":6.6,"vector":"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/E:U","level":"medium"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:38:00.257632Z"}],"nvd":[{"id":"CVE-2016-6580","description":"A HTTP/2 implementation built using any version of the Python priority library prior to version 1.2.0 could be targeted by a malicious peer by having that peer assign priority information for every possible HTTP/2 stream ID. The priority tree would happily continue to store the priority information for each stream, and would therefore allocate unbounded amounts of memory. Attempting to actually use a tree like this would also cause extremely high CPU usage to maintain the tree.","status":"published","published":"2017-01-10T15:59:00.377Z","modified":"2026-06-17T00:51:24.14Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"},{"version":"2.0","score":5,"vector":"AV:N/AC:L/Au:N/C:N/I:N/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-399"],"updated_at":"2026-11-02T14:03:33.686843Z"}],"osv":[{"id":"CVE-2016-6580","description":"A HTTP/2 implementation built using any version of the Python priority library prior to version 1.2.0 could be targeted by a malicious peer by having that peer assign priority information for every possible HTTP/2 stream ID. The priority tree would happily continue to store the priority information for each stream, and would therefore allocate unbounded amounts of memory. Attempting to actually use a tree like this would also cause extremely high CPU usage to maintain the tree.","status":"published","published":"2017-01-10T15:59:00.377Z","modified":"2026-10-24T10:30:52.710711405Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T15:44:02.776224Z"},{"id":"GHSA-h3q4-6j7f-r24c","title":"priority vulnerable to denial of service","description":"A HTTP/2 implementation built using any version of the Python priority library prior to version 1.2.0 could be targeted by a malicious peer by having that peer assign priority information for every possible HTTP/2 stream ID. The priority tree would happily continue to store the priority information for each stream, and would therefore allocate unbounded amounts of memory. Attempting to actually use a tree like this would also cause extremely high CPU usage to maintain the tree.","status":"published","published":"2022-05-17T03:02:35Z","modified":"2024-08-30T23:58:07.907253Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"},{"version":"4.0","score":6.6,"vector":"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/E:U","level":"medium"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:46:48.546324Z"},{"id":"PYSEC-2017-93","description":"A HTTP/2 implementation built using any version of the Python priority library prior to version 1.2.0 could be targeted by a malicious peer by having that peer assign priority information for every possible HTTP/2 stream ID. The priority tree would happily continue to store the priority information for each stream, and would therefore allocate unbounded amounts of memory. Attempting to actually use a tree like this would also cause extremely high CPU usage to maintain the tree.","status":"published","published":"2017-01-10T15:59:00Z","modified":"2026-06-10T17:01:38.249933537Z","updated_at":"2026-11-02T15:52:51.645172Z"}]}}