{"id":"CVE-2026-55254","summary":"NCalc: Denial of Service via Unbounded and Non-Terminating Factorial Evaluation","details":"NCalc is a fast, lightweight expression evaluator for .NET. Prior to 6.1.1, the factorial operator implementation in src/NCalc.Core/Helpers/MathHelper.cs permits specially crafted expressions with extremely large factorial operands, causing excessive CPU consumption or a non-terminating loop due to integer overflow in the factorial calculation logic when applications evaluate untrusted expressions. This issue is fixed in version 6.1.1.","aliases":["GHSA-3w5p-95mh-gq75"],"modified":"2026-08-20T03:54:29.799400108Z","published":"2026-07-17T19:55:16.728Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55254.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-190","CWE-770"]},"references":[{"type":"WEB","url":"https://github.com/ncalc/ncalc/releases/tag/v6.1.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55254.json"},{"type":"ADVISORY","url":"https://github.com/ncalc/ncalc/security/advisories/GHSA-3w5p-95mh-gq75"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55254"},{"type":"FIX","url":"https://github.com/ncalc/ncalc/commit/eeb6155ee1899b1fdf2cda3da35a4f0ca93ffd6a"},{"type":"FIX","url":"https://github.com/ncalc/ncalc/pull/575"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/ncalc/ncalc","events":[{"introduced":"0"},{"fixed":"e885002a859c72eaf00b16a92d239960d289742f"},{"fixed":"eeb6155ee1899b1fdf2cda3da35a4f0ca93ffd6a"}],"database_specific":{"source":["CPE_RANGE","REFERENCES"],"cpe":"cpe:2.3:a:ncalc:ncalc:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"0"},{"fixed":"6.1.1"}]}}],"versions":["v5.10.0","v5.2.5","v5.2.3","5.2.1","v4.2.0","v4.0.0","v3.13.1","v2.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55254.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H"}]}