guzzle psr7 up to 2.10.1 deserialization

Summaryinfo

A vulnerability marked as problematic has been reported in guzzle psr7 up to 2.10.1. Affected by this vulnerability is an unknown functionality. This manipulation causes deserialization. This vulnerability only affects products that are no longer supported by the maintainer. This vulnerability is handled as CVE-2026-49214. The attack can be initiated remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability has been found in guzzle psr7 up to 2.10.1 and classified as problematic. Affected by this vulnerability is an unknown code. The manipulation with an unknown input leads to a deserialization vulnerability. The CWE definition for the vulnerability is CWE-502. The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid. As an impact it is known to affect integrity. The summary by CVE is:

guzzlehttp/psr7 is a PSR-7 HTTP message library implementation in PHP. Versions prior to 2.10.2 did not reject ASCII control characters, whitespace, or DEL in first-party URI host components. A vulnerable flow is: First, an application accepts a user-controlled URL. Second, the URL is used to construct a PSR-7 `Uri` or `Request`. Third, the host component contains CRLF or another header-unsafe character. Fourth, the host is copied into the PSR-7 `Host` header when no explicit `Host` header is provided. Finally, the request is serialized or sent by an HTTP client that does not independently reject the malformed host. In that flow, an attacker can cause the serialized request to contain additional attacker-controlled header lines. For example, a host containing `"\r\nX-Injected: yes"` can cause the generated `Host` header to span multiple HTTP header lines. Applications are affected when they use user-controlled URLs for outbound HTTP requests, URL forwarding, proxying, crawling, webhook delivery, or similar request-dispatch flows. In deployments involving HTTP/1.1 connection reuse, proxies, gateways, or load balancers, this malformed request may also contribute to request smuggling or cache poisoning, depending on how downstream components parse the request. The issue is patched in `2.10.2` and later. `1.x` is end-of-life and will not receive a patch. As a workaround, validate and reject all untrusted URI strings before constructing PSR-7 `Uri` or `Request` instances. Reject input containing ASCII control characters, whitespace, or DEL, including CRLF, tab, space, NUL, or DEL characters. Applications that forward requests should also ensure the final HTTP client or serializer rejects invalid URI and header data before writing requests to the network.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-49214 since 05/28/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available.

Upgrading to version 2.10.2 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-36240). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

• guzzle

Name

• psr7

Version

• 2.10.0
• 2.10.1

Support

• end of life

Website

• Product: https://github.com/guzzle/psr7/

CPE 2.3info

• 🔒
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CPE 2.2info

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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