Vulnerability Instance
Lookup for vulnerabilities affecting packages.
GET /api/vulnerabilities/22940?format=api
{ "url": "http://public2.vulnerablecode.io/api/vulnerabilities/22940?format=api", "vulnerability_id": "VCID-qz71-ek2u-8ybh", "summary": "Loofah has improper detection of disallowed URIs via `allowed_uri?`\n## Summary\n\n`Loofah::HTML5::Scrub.allowed_uri?` does not correctly reject `javascript:` URIs when the scheme is split by HTML entity-encoded control characters such as ` ` (carriage return), ` ` (line feed), or `	` (tab).\n\n## Details\n\nThe `allowed_uri?` method strips literal control characters before decoding HTML entities. Payloads like `java script:alert(1)` survive the control character strip, then ` ` is decoded to a carriage return, producing `java\\rscript:alert(1)`.\n\nNote that the Loofah sanitizer's default `sanitize()` path is **not affected** because Nokogiri decodes HTML entities during parsing before Loofah evaluates the URI protocol. This issue only affects direct callers of the `allowed_uri?` string-level helper when passing HTML-encoded strings.\n\n## Impact\n\nApplications that call `Loofah::HTML5::Scrub.allowed_uri?` to validate user-controlled URLs and then render approved URLs into `href` or other browser-interpreted URI attributes may be vulnerable to cross-site scripting (XSS).\n\nThis only affects Loofah `2.25.0`.\n\n## Mitigation\n\nUpgrade to Loofah >= `2.25.1`.\n\n## Credit\n\nResponsibly reported by HackOne user @smlee.", "aliases": [ { "alias": "GHSA-2j22-pr5w-6gq8" } ], "fixed_packages": [ { "url": "http://public2.vulnerablecode.io/api/packages/65210?format=api", "purl": "pkg:gem/loofah@2.25.1", "is_vulnerable": true, "affected_by_vulnerabilities": [ { "vulnerability": "VCID-amsh-qpt1-9qb7" } ], "resource_url": "http://public2.vulnerablecode.io/packages/pkg:gem/loofah@2.25.1" } ], "affected_packages": [ { "url": "http://public2.vulnerablecode.io/api/packages/65209?format=api", "purl": "pkg:gem/loofah@2.25.0", "is_vulnerable": true, "affected_by_vulnerabilities": [ { "vulnerability": "VCID-amsh-qpt1-9qb7" }, { "vulnerability": "VCID-qz71-ek2u-8ybh" } ], "resource_url": "http://public2.vulnerablecode.io/packages/pkg:gem/loofah@2.25.0" } ], "references": [ { "reference_url": "https://github.com/flavorjones/loofah", "reference_id": "", "reference_type": "", "scores": [ { "value": "2.3", "scoring_system": "cvssv4", "scoring_elements": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N" }, { "value": "LOW", "scoring_system": "generic_textual", "scoring_elements": "" } ], "url": "https://github.com/flavorjones/loofah" }, { "reference_url": "https://github.com/flavorjones/loofah/commit/f4ebc9c5193dde759a57541062e490e86fc7c068", "reference_id": "", "reference_type": "", "scores": [ { "value": "2.3", "scoring_system": "cvssv4", "scoring_elements": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N" }, { "value": "LOW", "scoring_system": "generic_textual", "scoring_elements": "" } ], "url": "https://github.com/flavorjones/loofah/commit/f4ebc9c5193dde759a57541062e490e86fc7c068" }, { "reference_url": "https://github.com/flavorjones/loofah/releases/tag/v2.25.1", "reference_id": "", "reference_type": "", "scores": [ { "value": "2.3", "scoring_system": "cvssv4", "scoring_elements": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N" }, { "value": "LOW", "scoring_system": "generic_textual", "scoring_elements": "" } ], "url": "https://github.com/flavorjones/loofah/releases/tag/v2.25.1" }, { "reference_url": "https://github.com/flavorjones/loofah/security/advisories/GHSA-46fp-8f5p-pf2m", "reference_id": "", "reference_type": "", "scores": [ { "value": "2.3", "scoring_system": "cvssv4", "scoring_elements": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N" }, { "value": "LOW", "scoring_system": "generic_textual", "scoring_elements": "" } ], "url": "https://github.com/flavorjones/loofah/security/advisories/GHSA-46fp-8f5p-pf2m" }, { "reference_url": "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/loofah/GHSA-46fp-8f5p-pf2m.yml", "reference_id": "", "reference_type": "", "scores": [ { "value": "2.3", "scoring_system": "cvssv4", "scoring_elements": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N" }, { "value": "LOW", "scoring_system": "generic_textual", "scoring_elements": "" } ], "url": "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/loofah/GHSA-46fp-8f5p-pf2m.yml" }, { "reference_url": "https://github.com/advisories/GHSA-2j22-pr5w-6gq8", "reference_id": "GHSA-2j22-pr5w-6gq8", "reference_type": "", "scores": [ { "value": "LOW", "scoring_system": "cvssv3.1_qr", "scoring_elements": "" } ], "url": "https://github.com/advisories/GHSA-2j22-pr5w-6gq8" } ], "weaknesses": [ { "cwe_id": 79, "name": "Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')", "description": "The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users." }, { "cwe_id": 116, "name": "Improper Encoding or Escaping of Output", "description": "The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved." }, { "cwe_id": 937, "name": "OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities", "description": "Weaknesses in this category are related to the A9 category in the OWASP Top Ten 2013." }, { "cwe_id": 1035, "name": "OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities", "description": "Weaknesses in this category are related to the A9 category in the OWASP Top Ten 2017." } ], "exploits": [], "severity_range_score": "0.1 - 3", "exploitability": "0.5", "weighted_severity": "2.7", "risk_score": 1.4, "resource_url": "http://public2.vulnerablecode.io/vulnerabilities/VCID-qz71-ek2u-8ybh" }