{"cve":"CVE-2026-32874","nvd":{"published":"2026-03-20T02:16:35.703","modified":"2026-07-15T02:20:01.790","status":"Modified","description":"UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. Versions 5.4.0 through 5.11.0 contain an accumulating memory leak in JSON parsing large (outside of the range [-2^63, 2^64 - 1]) integers. The leaked memory is a copy of the string form of the integer plus an additional NULL byte. The leak occurs irrespective of whether the integer parses successfully or is rejected due to having more than sys.get_int_max_str_digits() digits, meaning that any sized leak per malicious JSON can be achieved provided that there is no limit on the overall size of the payload. Any service that calls ujson.load()/ujson.loads()/ujson.decode() on untrusted inputs is affected and vulnerable to denial of service attacks. This issue has been fixed in version 5.12.0.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-401","CWE-772"],"references":["https://github.com/ultrajson/ultrajson/commit/4baeb950df780092bd3c89fc702a868e99a3a1d2","https://github.com/ultrajson/ultrajson/releases/tag/5.12.0","https://github.com/ultrajson/ultrajson/security/advisories/GHSA-wgvc-ghv9-3pmm","https://access.redhat.com/security/cve/CVE-2026-32874","https://bugzilla.redhat.com/show_bug.cgi?id=2449411"],"products":["ultrajson_project:ultrajson"],"source":"nvd","synced_at":"2026-10-19T22:26:19.218427112+00:00"},"epss":{"cve":"CVE-2026-32874","score":0.00497,"percentile":0.42654,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-wgvc-ghv9-3pmm","url":"https://osv.dev/vulnerability/GHSA-wgvc-ghv9-3pmm","summary":"UltraJSON has a Memory Leak parsing large integers allows DoS ","modified":"2026-09-10T03:50:41.558110605Z","packages":[{"ecosystem":"PyPI","name":"ujson","purl":"pkg:pypi/ujson","ranges":[">=5.4.0 <5.12.0"],"fixed":["5.12.0"]}]},{"id":"PYSEC-2026-2291","url":"https://osv.dev/vulnerability/PYSEC-2026-2291","summary":"","modified":"2026-07-13T07:15:45.403362007Z","packages":[{"ecosystem":"PyPI","name":"ujson","purl":"pkg:pypi/ujson","ranges":[">=5.4.0 <5.12.0"],"fixed":["5.12.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}