CVE-2024-21631
Integer overflow in URI leading to potential host spoofing
In short
Vapor's URL parser uses 16-bit integers to track positions in web addresses, causing it to fail on very long URLs. An attacker can exploit this by crafting a specially formatted URL with a padded port number to trick the application into connecting to a different server than intended.
Technical detail
CVE-2024-21631 exploits integer overflow in Vapor's `vapor_urlparser_parse` function, where `uint16_t` indexes overflow when parsing untrusted URIs with abnormally long components. By padding the port field with zeros, an attacker can cause the host validation to fail, enabling host spoofing attacks; applications using the URI type for input validation and URL routing are at risk.
Summary generated and translated by AI from the official description.
Vapor is an HTTP web framework for Swift. Prior to version 4.90.0, Vapor's `vapor_urlparser_parse` function uses `uint16_t` indexes when parsing a URI's components, which may cause integer overflows when parsing untrusted inputs. This vulnerability does not affect Vapor directly but could impact applications relying on the URI type for validating user input. The URI type is used in several places in Vapor. A developer may decide to use URI to represent a URL in their application (especially if that URL is then passed to the HTTP Client) and rely on its public properties and methods. However, URI may fail to properly parse a valid (albeit abnormally long) URL, due to string ranges being converted to 16-bit integers. An attacker may use this behavior to trick the application into accepting a URL to an untrusted destination. By padding the port number with zeros, an attacker can cause an integer overflow to occur when the URL authority is parsed and, as a result, spoof the host. Version 4.90.0 contains a patch for this issue. As a workaround, validate user input before parsing as a URI or, if possible, use Foundation's `URL` and `URLComponents` utilities.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Affected products
vapor · vaporWant to know if your infrastructure is exposed to this?
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