CVE-2026-86251
Description
A flaw was found in h3. A remote attacker could exploit a path traversal vulnerability in the serveStatic utility. This vulnerability arises from a double-decoding flaw, where specially crafted, double-encoded dot sequences in a request path are incorrectly processed. This allows an attacker to bypass security checks and read arbitrary files from backend storage systems, leading to information disclosure.
Statement
Moderate: A path traversal vulnerability exists in the serveStatic utility of h3 due to a double-decoding flaw. This issue allows an attacker to bypass path sanitization by using specially crafted double-encoded dot sequences, potentially leading to information disclosure from URL-based backends. The complexity of crafting such an attack contributes to its Moderate impact, as it requires specific input manipulation to exploit.
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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.9 | N/A | 5.9 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
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