CVE-2016-6580 json
priority vulnerable to denial of service
published 2017-01-10 9 y ago modified 2026-06-17 4 mo ago also GHSA-h3q4-6j7f-r24c , PYSEC-2017-93 , EUVD-2017-0099
- cvss
- 7.5
- version 3.0, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.8%
- EPSS 1.8% chance of exploitation in 30 days, percentile 79%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
Exploit prediction
1.84% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.0 | 7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVD | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:N/I:N/A:P |
| GitHub | 3.0 | 7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | priority | <1.2.0 |
1.2.0 |
Classification
References
-
github.com
/python-hyper/priority/commit/7d01a7dc4db83bce50f20d47caf4f37b403a3ecd
web
-
python-hyper.org
/priority/en/latest/security/CVE-2016-6580.html
web, mitigation, vendor-advisory
-
securityfocus.com
/bid/92311
vdb-entry, third-party-advisory, web
-
nvd.nist.gov
/vuln/detail/CVE-2016-6580
advisory
-
github.com
/pypa/advisory-database/tree/main/vulns/priority/PYSEC-2017-93.yaml
web
-
github.com
/python-hyper/priority
package
-
web.archive.org
/web/20160806004329/http://www.securityfocus.com/bid/92311
web
-
github.com
/advisories/GHSA-h3q4-6j7f-r24c
advisory
Sources
- CVE List CVE-2016-6580
- GitHub Advisory GHSA-h3q4-6j7f-r24c
- NVD CVE-2016-6580
- OSV PYSEC-2017-93
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.