{"cve":"CVE-2021-45958","nvd":{"published":"2022-01-01T00:15:08.813","modified":"2026-06-17T04:14:19.740","status":"Modified","description":"UltraJSON (aka ujson) through 5.1.0 has a stack-based buffer overflow in Buffer_AppendIndentUnchecked (called from encode). Exploitation can, for example, use a large amount of indentation.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-787"],"references":["https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=36009","https://github.com/google/oss-fuzz-vulns/blob/main/vulns/ujson/OSV-2021-955.yaml","https://github.com/ultrajson/ultrajson/issues/501","https://github.com/ultrajson/ultrajson/issues/502#issuecomment-1031747284","https://github.com/ultrajson/ultrajson/pull/504"],"products":["debian:debian_linux","fedoraproject:fedora","ultrajson_project:ultrajson"],"source":"nvd","synced_at":"2026-10-19T21:26:33.761856376+00:00"},"epss":{"cve":"CVE-2021-45958","score":0.01667,"percentile":0.76751,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-fh56-85cw-5pq6","url":"https://osv.dev/vulnerability/GHSA-fh56-85cw-5pq6","summary":"UltraJSON vulnerable to Out-of-bounds Write","modified":"2024-11-18T23:02:13.081685Z","packages":[{"ecosystem":"PyPI","name":"ujson","purl":"pkg:pypi/ujson","ranges":[">=1.34 <5.2.0"],"fixed":["5.2.0"]}]},{"id":"PYSEC-2022-25","url":"https://osv.dev/vulnerability/PYSEC-2022-25","summary":"","modified":"2023-11-08T04:07:24.600926Z","packages":[{"ecosystem":"PyPI","name":"ujson","purl":"pkg:pypi/ujson","ranges":[">=4.0.2 <5.1.0"],"fixed":["5.1.0"]}]}],"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."]}