SB2026072227 - Multiple vulnerabilities in fast-uri

Description

This security bulletin contains information about 2 vulnerabilities.

1) Path traversal (CVE-ID: CVE-2026-6321)

CWE-ID: CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to bypass path-based policy checks.

The vulnerability exists due to path traversal in the normalize() and equal() functions when processing percent-encoded path separators and dot segments in attacker-controlled URLs. A remote attacker can supply a specially crafted URL to bypass path-based policy checks.

Applications that normalize or compare attacker-controlled URLs to enforce path-based policy are affected.

2) Interpretation Conflict (CVE-ID: CVE-2026-6322)

CWE-ID: CWE-436 - Interpretation Conflict

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to bypass host-based security checks and route requests to an unintended authority.

The vulnerability exists due to interpretation conflict in the URI host component when processing percent-encoded authority delimiters. A remote attacker can supply a specially crafted URL to bypass host-based security checks and route requests to an unintended authority.

This issue can affect applications that normalize untrusted URLs before host allowlist checks, redirect validation, or outbound request routing.

Remediation

Install update from vendor's website.

References

• https://github.com/fastify/fast-uri/security/advisories/GHSA-q3j6-qgpj-74h6
• https://github.com/fastify/fast-uri/security/advisories/GHSA-v39h-62p7-jpjc