CVE-2026-18446 - High Severity Vulnerability
Vulnerable Library - fast-uri-3.1.0.tgz
Dependency-free RFC 3986 URI toolbox
Library home page: https://registry.npmjs.org/fast-uri/-/fast-uri-3.1.0.tgz
Sample Path to Dependency File: /package.json
Path to vulnerable library: /node_modules/fast-uri/package.json
Dependency Hierarchy:
- muon-0.0.2-beta.64.tgz (Root Library)
- building-rollup-3.0.2.tgz
- rollup-plugin-workbox-8.1.3.tgz
- workbox-build-7.4.0.tgz
- ajv-8.18.0.tgz
- ❌ fast-uri-3.1.0.tgz (Vulnerable Library)
Found in HEAD commit: f62742a486a7acc9074524b4461667e5e1e3ed9f
Found in base branch: main
Vulnerability Details
fast-uri before 4.1.2, 3.1.5, and 2.4.4 requires a literal double forward slash to recognize a URI authority, so a reference that uses a backslash based introducer in place of it (backslash backslash, forward slash backslash, or backslash forward slash) is parsed with no authority and folds into the path. Node's native WHATWG URL parser instead treats a backslash as interchangeable with a forward slash for special schemes, so the two parsers extract different hosts from the same input. Applications that use fast-uri to enforce host based policy such as allowlists, SSRF filtering, or redirect validation before passing the same URL into Node's URL or fetch consumers can be steered to an unintended host. Upgrade to fast-uri 4.1.2, 3.1.5, or 2.4.4.
Publish Date: 2026-07-31
URL: CVE-2026-18446
CVSS 3 Score Details (7.5)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: Low
- Privileges Required: None
- User Interaction: None
- Scope: Unchanged
- Impact Metrics:
- Confidentiality Impact: None
- Integrity Impact: High
- Availability Impact: None
For more information on CVSS3 Scores, click here.
Suggested Fix
Type: Upgrade version
Origin: GHSA-7p8r-x3mc-p8w7
Release Date: 2026-07-31
Fix Resolution: fast-uri - 2.4.4,fast-uri - 3.1.5,fast-uri - 4.1.2,https://github.com/fastify/fast-uri.git - v3.1.5,https://github.com/fastify/fast-uri.git - v4.1.2,https://github.com/fastify/fast-uri.git - v2.4.4
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CVE-2026-18446 - High Severity Vulnerability
Dependency-free RFC 3986 URI toolbox
Library home page: https://registry.npmjs.org/fast-uri/-/fast-uri-3.1.0.tgz
Sample Path to Dependency File: /package.json
Path to vulnerable library: /node_modules/fast-uri/package.json
Dependency Hierarchy:
Found in HEAD commit: f62742a486a7acc9074524b4461667e5e1e3ed9f
Found in base branch: main
fast-uri before 4.1.2, 3.1.5, and 2.4.4 requires a literal double forward slash to recognize a URI authority, so a reference that uses a backslash based introducer in place of it (backslash backslash, forward slash backslash, or backslash forward slash) is parsed with no authority and folds into the path. Node's native WHATWG URL parser instead treats a backslash as interchangeable with a forward slash for special schemes, so the two parsers extract different hosts from the same input. Applications that use fast-uri to enforce host based policy such as allowlists, SSRF filtering, or redirect validation before passing the same URL into Node's URL or fetch consumers can be steered to an unintended host. Upgrade to fast-uri 4.1.2, 3.1.5, or 2.4.4.
Publish Date: 2026-07-31
URL: CVE-2026-18446
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: Low
- Privileges Required: None
- User Interaction: None
- Scope: Unchanged
- Impact Metrics:
- Confidentiality Impact: None
- Integrity Impact: High
- Availability Impact: None
For more information on CVSS3 Scores, click here.Type: Upgrade version
Origin: GHSA-7p8r-x3mc-p8w7
Release Date: 2026-07-31
Fix Resolution: fast-uri - 2.4.4,fast-uri - 3.1.5,fast-uri - 4.1.2,https://github.com/fastify/fast-uri.git - v3.1.5,https://github.com/fastify/fast-uri.git - v4.1.2,https://github.com/fastify/fast-uri.git - v2.4.4
Step up your Open Source Security Game with Mend here