How severe is CVE-2024-21631?

CVE-2024-21631 has a CVSS score of 6.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2024-21631?

CVE-2024-21631 affects the following packages: github.com/vapor/vapor (SwiftURL). Ecosystems affected: SwiftURL.

How do I fix CVE-2024-21631?

Update github.com/vapor/vapor to 4.90.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-21631 is resolved across your whole dependency graph.

How do I detect CVE-2024-21631 in my SwiftURL dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/vapor/vapor. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2024-21631 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2024-21631?

O3 pinpoints whether CVE-2024-21631 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2024-21631 actively exploited in the wild?

No public exploit code has been indexed for CVE-2024-21631 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2024-21631?

CVE-2024-21631 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 44th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2024-21631?

CVE-2024-21631 is classified as Improper Input Validation (CWE-20), CWE-190 (CWE-190), CWE-1104 (CWE-1104). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2024-21631 published, and has it been updated?

CVE-2024-21631 was published on January 3, 2024 and was last updated on April 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 SwiftURL

CVE-2024-21631

MEDIUM

Integer overflow in URI leading to potential host spoofing

Also known asGHSA-r6r4-5pr8-gjcp

Published

Jan 3, 2024

Updated

Apr 12, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk44th percentile+0.29%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

📦github.com/vapor/vapor

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects SwiftURL packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦SwiftURL	`github.com/vapor/vapor`	all versions	4.90.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/vapor/vapor. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/vapor/vapor to 4.90.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-21631 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2024-21631 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2024-21631. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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, U

O3 Security · Impact-Aware SCA

Is CVE-2024-21631 in your dependencies?

O3 detects CVE-2024-21631 across SwiftURL dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works