medium4.8
CVE-2026-55254
NCalc: Denial of Service via Unbounded and Non-Terminating Factorial Evaluation
Impact
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
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| nuget | NCalc.Core | < 6.1.1 | 6.1.1 |
| nuget | NCalcSync | < 6.1.1 | 6.1.1 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Ncalc | Ncalc | before 6.1.1 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-3w5p-95mh-gq75
- 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