CVE-2026-13676
Description
A flaw was found in fast-uri. This vulnerability occurs because fast-uri fails to properly convert Unicode (Internationalized Domain Name - IDN) hostnames for HTTP-family URLs. This can lead to a situation where security policies, such as denylists or redirect validations, are bypassed when applications use fast-uri to enforce these policies before passing the URL to another parser. A remote attacker could exploit this to circumvent security controls and potentially access unauthorized resources or perform malicious redirects.
Statement
This Important flaw in fast-uri allows a remote attacker to bypass host-based security policies. Applications that rely on fast-uri for URL parsing and policy enforcement, such as denylists or redirect validations, can be circumvented due to inconsistent handling of Unicode hostnames. This discrepancy between fast-uri and other URL parsers could lead to unauthorized resource access or malicious redirects in affected Red Hat products.
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)
Access Control
Technical Impact: Bypass Protection Mechanism
Frequently Asked Questions
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