CVE-2026-55254
Published:July 17, 2026
Updated:July 21, 2026
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 Packages
NCalc.Core (DOT_NET):
Affected version(s) >=4.3.0.13 <6.1.1Fix Suggestion:
Update to version 6.1.1NCalcSync (DOT_NET):
Affected version(s) >=4.3.0.13 <6.1.1Fix Suggestion:
Update to version 6.1.1https://github.com/ncalc/ncalc.git (GITHUB):
Affected version(s) >=v4.3.0 <v6.1.1Fix Suggestion:
Update to version v6.1.1ncalcsync (NUGET):
Affected version(s) >=2.0.0 <6.1.1Fix Suggestion:
Update to version 6.1.1ncalc.core (NUGET):
Affected version(s) >=4.3.0 <6.1.1Fix Suggestion:
Update to version 6.1.1Related Resources (5)
Do you need more information?
Contact UsCVSS v4
Base Score:
5.9
Attack Vector
ADJACENT
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
PASSIVE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
4.8
Attack Vector
ADJACENT
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
EPSS
Base Score:
0.19