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 had a vulnerability where inbound HEADERS frames were not properly validated, allowing control characters such as CR, LF, NUL, and SP to pass through to an HTTP/1.1 backend via the HTTP/2-to-HTTP/1 codec. This flaw could enable HTTP request smuggling or response splitting attacks. The issue is fixed 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. This omission allows control characters (CR, LF, NUL, SP, and others) to be forwarded to an HTTP/1.1 backend through the NIOHTTP2 codec that translates HTTP/2 to HTTP/1. Such control characters can be exploited to perform HTTP request smuggling or response splitting attacks. The vulnerability affects all versions prior to 1.45.0, where it has been addressed.
Potential Impact
If exploited, this vulnerability could allow an attacker to manipulate HTTP requests or responses by injecting control characters, potentially leading to HTTP request smuggling or response splitting. These attacks can cause security issues such as bypassing security controls, cache poisoning, or cross-user data leakage. No known exploits are reported in the wild at this time.
Mitigation Recommendations
A fix is available in swift-nio-http2 version 1.45.0. Users should upgrade to version 1.45.0 or later to remediate this vulnerability. No additional mitigation steps are indicated.
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 had a vulnerability where inbound HEADERS frames were not properly validated, allowing control characters such as CR, LF, NUL, and SP to pass through to an HTTP/1.1 backend via the HTTP/2-to-HTTP/1 codec. This flaw could enable HTTP request smuggling or response splitting attacks. The issue is fixed in swift-nio-http2 version 1.45.0.
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.
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. This omission allows control characters (CR, LF, NUL, SP, and others) to be forwarded to an HTTP/1.1 backend through the NIOHTTP2 codec that translates HTTP/2 to HTTP/1. Such control characters can be exploited to perform HTTP request smuggling or response splitting attacks. The vulnerability affects all versions prior to 1.45.0, where it has been addressed.
Potential Impact
If exploited, this vulnerability could allow an attacker to manipulate HTTP requests or responses by injecting control characters, potentially leading to HTTP request smuggling or response splitting. These attacks can cause security issues such as bypassing security controls, cache poisoning, or cross-user data leakage. No known exploits are reported in the wild at this time.
Mitigation Recommendations
A fix is available in swift-nio-http2 version 1.45.0. Users should upgrade to version 1.45.0 or later to remediate this vulnerability. No additional mitigation steps are indicated.
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: 07/23/2026, 19:37:16 UTC
Last updated: 07/23/2026, 19:37:16 UTC
Views: 4
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