Fast Uri
Monthly
Host-based security policy bypass in the fast-uri Node.js URI parser (versions 2.3.1 through 3.1.2 and 4.0.0) lets remote attackers defeat denylists, loopback filters, redirect validation, and SSRF/proxy-routing controls by supplying Unicode (IDN) hostnames. Because fast-uri's IDN path invokes a non-existent helper on the global URL constructor, it leaves the host in raw Unicode form while normalize() and equal() report a host that differs from what Node's WHATWG URL or fetch ultimately resolve, producing a parser-differential bypass. No public exploit is identified at time of analysis, but the bypass is trivially reproducible and primarily enables SSRF-style integrity attacks.
Authority confusion in fast-uri JavaScript library allows remote attackers to bypass URL validation security controls. The normalize() function improperly decodes percent-encoded at-signs (%40) in hostnames, then re-serializes them as raw userinfo delimiters, causing URLs like 'http://trusted.com%40evil.com' to resolve to 'evil.com' instead of 'trusted.com'. Applications using fast-uri to validate URLs against allowlists or for redirect validation can be tricked into connecting to attacker-controlled domains. CVSS 7.5 (AV:N/AC:L/PR:N/UI:N) indicates trivial remote exploitation with no authentication. EPSS data not available; no confirmed active exploitation (not in CISA KEV). Vendor patch released in version 3.1.2.
Path normalization bypass in fast-uri 3.1.0 and earlier allows remote attackers to circumvent path-based access controls through percent-encoded path traversal sequences. The normalize() and equal() functions decode URL-encoded separators (%2F) and dot segments (%2E) before applying normalization rules, causing distinct URIs to collapse onto identical normalized paths. Applications relying on fast-uri for URL validation in authorization checks can be tricked into allowing access to restricted resources. EPSS exploitation probability not yet calculated given recent disclosure; no active exploitation confirmed (not in CISA KEV), but attack vector is trivial (CVSS AV:N/AC:L/PR:N/UI:N) and patch is available in version 3.1.1.
Host-based security policy bypass in the fast-uri Node.js URI parser (versions 2.3.1 through 3.1.2 and 4.0.0) lets remote attackers defeat denylists, loopback filters, redirect validation, and SSRF/proxy-routing controls by supplying Unicode (IDN) hostnames. Because fast-uri's IDN path invokes a non-existent helper on the global URL constructor, it leaves the host in raw Unicode form while normalize() and equal() report a host that differs from what Node's WHATWG URL or fetch ultimately resolve, producing a parser-differential bypass. No public exploit is identified at time of analysis, but the bypass is trivially reproducible and primarily enables SSRF-style integrity attacks.
Authority confusion in fast-uri JavaScript library allows remote attackers to bypass URL validation security controls. The normalize() function improperly decodes percent-encoded at-signs (%40) in hostnames, then re-serializes them as raw userinfo delimiters, causing URLs like 'http://trusted.com%40evil.com' to resolve to 'evil.com' instead of 'trusted.com'. Applications using fast-uri to validate URLs against allowlists or for redirect validation can be tricked into connecting to attacker-controlled domains. CVSS 7.5 (AV:N/AC:L/PR:N/UI:N) indicates trivial remote exploitation with no authentication. EPSS data not available; no confirmed active exploitation (not in CISA KEV). Vendor patch released in version 3.1.2.
Path normalization bypass in fast-uri 3.1.0 and earlier allows remote attackers to circumvent path-based access controls through percent-encoded path traversal sequences. The normalize() and equal() functions decode URL-encoded separators (%2F) and dot segments (%2E) before applying normalization rules, causing distinct URIs to collapse onto identical normalized paths. Applications relying on fast-uri for URL validation in authorization checks can be tricked into allowing access to restricted resources. EPSS exploitation probability not yet calculated given recent disclosure; no active exploitation confirmed (not in CISA KEV), but attack vector is trivial (CVSS AV:N/AC:L/PR:N/UI:N) and patch is available in version 3.1.1.