CVE-2024-21631
Integer overflow in URI leading to potential host spoofing
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
6.5
Integer overflow in URI leading to potential host spoofing
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.
- Record
CVE-2024-21631- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-20, CWE-190, CWE-1104
- Updated
- 2026-11-02
EUVDEUVD-2024-0412
6.5
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.
- Record
EUVD-2024-0412- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-r6r4-5pr8-gjcp
6.5
Vapor contains an integer overflow in URI leading to potential host spoofing
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 behaviour 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.
Impact
Users attempting to treat untrusted input as a URI are vulnerable to a host spoofing attack due to an integer overflow.
Workarounds
Validate user input before parsing as a URI or, if possible, use Foundation's URL and URLComponents utilities.
- Record
GHSA-r6r4-5pr8-gjcp- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-190, CWE-1104
- Updated
- 2026-11-02
NVD
6.5
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.
- Record
CVE-2024-21631- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-20, CWE-190, CWE-1104
- Updated
- 2026-11-02
OSV
6.5
Integer overflow in URI leading to potential host spoofing
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.
- Record
CVE-2024-21631- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-1104, CWE-190, CWE-20
- Updated
- 2026-11-02
OSVGHSA-r6r4-5pr8-gjcp
6.5
Vapor contains an integer overflow in URI leading to potential host spoofing
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 behaviour 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.
Impact
Users attempting to treat untrusted input as a URI are vulnerable to a host spoofing attack due to an integer overflow.
Workarounds
Validate user input before parsing as a URI or, if possible, use Foundation's URL and URLComponents utilities.
- Record
GHSA-r6r4-5pr8-gjcp- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-1104, CWE-190
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/vapor/vaporSwiftURL |
through 4.89.3 | 4.90.0 |
github.com/vapor/vaporSwiftURL |
before 4.90.0 | 4.90.0 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2024-21631 is a medium vulnerability (CVSS 6.5) in Vapor, published January 3, 2024. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.60%, the 48th percentile. Fixed in github.com/vapor/vapor 4.90.0.
References
github.com/vapor/vapor/security/advisories/GHSA-r6r4-5pr8-gjcp
github.com/vapor/vapor/commit/6db3d917b5ce5024a84eb265ef65691383305d70
nvd.nist.gov/vuln/detail/CVE-2024-21631
github.com/advisories/GHSA-r6r4-5pr8-gjcp
github.com/CVEProject/cvelistV5/tree/main/cves/2024/21xxx/CVE-2024-21631.json
github.com/vapor/vapor