{"id":"CVE-2026-55254","state":"PUBLISHED","title":"NCalc: Denial of Service via Unbounded and Non-Terminating Factorial Evaluation","description":"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.","publishedAt":"2026-07-17T19:55:16.728Z","updatedAt":"2026-07-20T18:07:31.078Z","severity":{"score":4.8,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["ncalc ncalc"],"affected":[{"vendor":"ncalc","product":"ncalc","versions":[{"version":"< 6.1.1","status":"affected"}]}],"references":["https://github.com/ncalc/ncalc/security/advisories/GHSA-3w5p-95mh-gq75","https://github.com/ncalc/ncalc/pull/575","https://github.com/ncalc/ncalc/commit/eeb6155ee1899b1fdf2cda3da35a4f0ca93ffd6a","https://github.com/ncalc/ncalc/releases/tag/v6.1.1"],"weaknesses":["CWE-770","CWE-190"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/55xxx/CVE-2026-55254.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-55254","state":"PUBLISHED","datePublished":"2026-07-17T19:55:16.728Z","dateUpdated":"2026-07-20T18:07:31.078Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-16T16:44:00.625Z"},"containers":{"cna":{"title":"NCalc: Denial of Service via Unbounded and Non-Terminating Factorial Evaluation","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"ncalc","product":"ncalc","versions":[{"version":"< 6.1.1","status":"affected"}]}],"references":[{"url":"https://github.com/ncalc/ncalc/security/advisories/GHSA-3w5p-95mh-gq75","name":"https://github.com/ncalc/ncalc/security/advisories/GHSA-3w5p-95mh-gq75","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/ncalc/ncalc/pull/575","name":"https://github.com/ncalc/ncalc/pull/575","tags":["x_refsource_MISC"]},{"url":"https://github.com/ncalc/ncalc/commit/eeb6155ee1899b1fdf2cda3da35a4f0ca93ffd6a","name":"https://github.com/ncalc/ncalc/commit/eeb6155ee1899b1fdf2cda3da35a4f0ca93ffd6a","tags":["x_refsource_MISC"]},{"url":"https://github.com/ncalc/ncalc/releases/tag/v6.1.1","name":"https://github.com/ncalc/ncalc/releases/tag/v6.1.1","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"ADJACENT_NETWORK","availabilityImpact":"HIGH","baseScore":4.8,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-770","lang":"en","description":"CWE-770: Allocation of Resources Without Limits or Throttling","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-190","lang":"en","description":"CWE-190: Integer Overflow or Wraparound","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-07-17T19:55:16.728Z"},"source":{"advisory":"GHSA-3w5p-95mh-gq75","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-20T18:06:03.191078Z","id":"CVE-2026-55254","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-20T18:07:31.078Z"}}]}}}