CVE-2026-55254

NCalc: Denial of Service via Unbounded and Non-Terminating Factorial Evaluation

State: Published
Severity: 4.8 Medium
Published: Jul 17, 2026
Updated: Jul 20, 2026
Reserved: Jun 16, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	4.8 Medium	CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H	GitHub_M

Weaknesses

CWE-770 Allocation of Resources Without Limits or Throttling
CWE-190 Integer Overflow or Wraparound

Affected Products

Product	Versions
ncalcncalc	< 6.1.1Affected

References

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