HTTP Response Splitting Affecting guzzlehttp/psr7 package, versions <2.10.2
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PHP-GUZZLEHTTPPSR7-17318030
- published12 Jun 2026
- disclosed11 Jun 2026
- creditVolker Dusch
Introduced: 11 Jun 2026
NewCVE-2026-49214 (opens in a new tab)How to fix?
Upgrade guzzlehttp/psr7 to version 2.10.2 or higher.
Overview
Affected versions of this package are vulnerable to HTTP Response Splitting via the host component of a URI when constructing a PSR-7 Uri or Request. An attacker can inject arbitrary HTTP headers by supplying a crafted host value containing ASCII control characters, such as CRLF, which are then copied into the Host header and serialized in outbound HTTP requests. This can lead to the injection of additional attacker-controlled header lines, potentially enabling further attacks such as request smuggling or cache poisoning in certain deployment scenarios involving proxies, gateways, or load balancers.