CVE-2026-75899
Description
A flaw was found in fast-uri, a URI parser for Node.js. The component incorrectly decodes percent escapes in a hostname twice during URI parsing and authority recomposition. This double decoding can allow a remote attacker to manipulate a URI to point to a different network destination, such as a loopback address. This vulnerability can lead to Server-Side Request Forgery (SSRF) and bypass host-based security policies.
Statement
This flaw in the fast-uri library, used by applications for URI parsing, allows for Server-Side Request Forgery (SSRF) and host-policy bypass. By crafting a doubly percent-encoded hostname in an untrusted HTTP-family URI, an attacker could redirect internal application requests to arbitrary network destinations, potentially bypassing security controls and accessing internal services. This risk is present in Red Hat products that process untrusted URIs using affected versions of fast-uri.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Understanding the Weakness (CWE)
Integrity
Technical Impact: Unexpected State
Frequently Asked Questions
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