CVE-2026-64785: SwiftNIO HTTP/2 was missing validation on inbound HEADERS frames that let CR, LF, NUL, SP and other control characters reach an HTTP/1.1 backend through NIOHTTP2's HTTP/2-to-HTTP/1 codec, enabling HTTP request smuggling or response splitting. in Apple swift-nio-http2
SwiftNIO HTTP/2 was missing validation on inbound HEADERS frames that let CR, LF, NUL, SP and other control characters reach an HTTP/1.1 backend through NIOHTTP2's HTTP/2-to-HTTP/1 codec, enabling HTTP request smuggling or response splitting. This vulnerability is addressed in swift-nio-http2 version 1.45.0.
AI Analysis
Technical Summary
The vulnerability in Apple swift-nio-http2 involves missing validation on inbound HTTP/2 HEADERS frames. Specifically, control characters including carriage return (CR), line feed (LF), null (NUL), space (SP), and others could pass through the HTTP/2-to-HTTP/1 codec to the backend HTTP/1.1 server. This improper sanitization allows attackers to perform HTTP request smuggling or response splitting attacks. The issue is tracked as CVE-2026-64785 and is fixed in version 1.45.0 of swift-nio-http2.
Potential Impact
An attacker can exploit this vulnerability to perform HTTP request smuggling or response splitting against HTTP/1.1 backends behind the vulnerable swift-nio-http2 HTTP/2-to-HTTP/1 codec. This can lead to manipulation of HTTP requests or responses, potentially bypassing security controls or causing unintended behavior in web applications. The CVSS score of 5.3 reflects a medium severity with no confidentiality or availability impact but with integrity impact.
Mitigation Recommendations
Upgrade swift-nio-http2 to version 1.45.0 or later, where this validation issue has been addressed. No other official remediation or temporary fixes are indicated. Patch status is confirmed by the vendor advisory stating the fix is in version 1.45.0.
CVE-2026-64785: SwiftNIO HTTP/2 was missing validation on inbound HEADERS frames that let CR, LF, NUL, SP and other control characters reach an HTTP/1.1 backend through NIOHTTP2's HTTP/2-to-HTTP/1 codec, enabling HTTP request smuggling or response splitting. in Apple swift-nio-http2
Description
SwiftNIO HTTP/2 was missing validation on inbound HEADERS frames that let CR, LF, NUL, SP and other control characters reach an HTTP/1.1 backend through NIOHTTP2's HTTP/2-to-HTTP/1 codec, enabling HTTP request smuggling or response splitting. This vulnerability is addressed in swift-nio-http2 version 1.45.0.
CVSS v3.1
Score 5.3medium
Affected software
pkg:swift/apple/swift-nio-http2Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in Apple swift-nio-http2 involves missing validation on inbound HTTP/2 HEADERS frames. Specifically, control characters including carriage return (CR), line feed (LF), null (NUL), space (SP), and others could pass through the HTTP/2-to-HTTP/1 codec to the backend HTTP/1.1 server. This improper sanitization allows attackers to perform HTTP request smuggling or response splitting attacks. The issue is tracked as CVE-2026-64785 and is fixed in version 1.45.0 of swift-nio-http2.
Potential Impact
An attacker can exploit this vulnerability to perform HTTP request smuggling or response splitting against HTTP/1.1 backends behind the vulnerable swift-nio-http2 HTTP/2-to-HTTP/1 codec. This can lead to manipulation of HTTP requests or responses, potentially bypassing security controls or causing unintended behavior in web applications. The CVSS score of 5.3 reflects a medium severity with no confidentiality or availability impact but with integrity impact.
Mitigation Recommendations
Upgrade swift-nio-http2 to version 1.45.0 or later, where this validation issue has been addressed. No other official remediation or temporary fixes are indicated. Patch status is confirmed by the vendor advisory stating the fix is in version 1.45.0.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- apple
- Date Reserved
- 2026-07-20T18:11:03.398Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a626a069c2644c7f89416d4
Added to database: 07/23/2026, 19:22:46 UTC
Last enriched: 07/30/2026, 22:49:29 UTC
Last updated: 09/06/2026, 10:52:10 UTC
Views: 98
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