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

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Summary

CVECVE-2026-55254
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-17 20:17:27 UTC
Updated2026-07-17 20:17:27 UTC
DescriptionNCalc 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.

Risk And Classification

Primary CVSS: v3.1 4.8 MEDIUM from [email protected]

CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H

Problem Types: CWE-190 | CWE-770 | CWE-770 CWE-770: Allocation of Resources Without Limits or Throttling | CWE-190 CWE-190: Integer Overflow or Wraparound

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary4.8MEDIUMCVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H
3.1CNADECLARED4.8MEDIUMCVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Adjacent
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Ncalc Ncalc affected < 6.1.1 Not specified

References

ReferenceSourceLinkTags
github.com/ncalc/ncalc/releases/tag/v6.1.1 [email protected] github.com
github.com/ncalc/ncalc/pull/575 [email protected] github.com
github.com/ncalc/ncalc/commit/eeb6155ee1899b1fdf2cda3da35a4f0ca93ffd6a [email protected] github.com
github.com/ncalc/ncalc/security/advisories/GHSA-3w5p-95mh-gq75 [email protected] github.com
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