An Input Validation Vulnerability exists in Joel Christner .NET C# packages…
Priority MEDIUM 46CWE-704Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub. Impact type from CWE-704 and the CVSS impact.
Summary
An Input Validation Vulnerability exists in Joel Christner .NET C# packages WatsonWebserver, IpMatcher 1.0.4.1 and below (IpMatcher) and 4.1.3 and below (WatsonWebserver) due to insufficient validation of input IP addresses and netmasks against the internal Matcher list of IP addresses and subnets.
Why it matters now
EPSS 0.02052 81st percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed IpMatcher (NuGet): 1.0.4.2
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
| — | IpMatcher (NuGet) | before 1.0.4.2 | 1.0.4.2 | Patch available | GHSA-qj93-37f5-mr29 |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
- IpMatcher (NuGet) Vendor— Affected before 1.0.4.2 Fixed in 1.0.4.2 Patch available GHSA-qj93-37f5-mr29
CPE configurations NVD · 2
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:ipmatcher_project:ipmatcher:*:*:*:*:*:*:*:* | up to 1.0.4.1 | Vulnerable | Ipmatcher Project |
| cpe:2.3:a:watsonwebserver_project:watsonwebserver:*:*:*:*:*:*:*:* | up to 4.1.3 | Vulnerable | Watsonwebserver Project |
- cpe:2.3:a:ipmatcher_project:ipmatcher:*:*:*:*:*:*:*:* Versions up to 1.0.4.1 Vulnerable ·Ipmatcher Project
- cpe:2.3:a:watsonwebserver_project:watsonwebserver:*:*:*:*:*:*:*:* Versions up to 4.1.3 Vulnerable ·Watsonwebserver Project
Remediation
- Fix · GHSA-qj93-37f5-mr29 IpMatcher (NuGet) Fixed in 1.0.4.2 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2021-33318
- 2026-10-03 Alias added: GHSA-qj93-37f5-mr29
References
Sources
- CVE-2021-33318 · CVE Program
- CVE-2021-33318 · NVD
- FIRST EPSS
- GHSA-qj93-37f5-mr29 · GitHub Advisory Database · CC BY 4.0
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