# CVE-2026-48998: php-guzzlehttp-psr7: guzzlehttp/psr7 is a PSR-7 HTTP message library implementation in PHP

CVE-2026-48998 is fixed in php-guzzlehttp-psr7 on 1 platform, first by DEBIAN-CVE-2026-48998, released June 24, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-48998
- Priority: Routine
- CVSS: 5.3 (medium)
- EPSS: 0.0020
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 11, 2026

## Description

guzzlehttp/psr7 is a PSR-7 HTTP message library implementation in PHP. Versions prior to 2.10.2 contain improper Host header validation when parsing raw HTTP request messages and when deriving a server request URI from server variables. An attacker can provide a malformed Host header containing URI authority delimiters, such as `trusted.example@evil.example`. When the Host value is used to construct a URI, the malformed value can be reinterpreted as URI userinfo and host. This can cause the PSR-7 request URI host to differ from the original Host header value. Applications are affected if they parse attacker-controlled raw HTTP requests with `GuzzleHttp\Psr7\Message::parseRequest()` or the legacy 1.x `GuzzleHttp\Psr7\parse_request()` function, or if they build server requests from attacker-controlled server variables, then rely on the resulting URI host for routing, allow-list checks, or forwarding decisions. In affected forwarding or gateway scenarios, this may cause requests or credentials to be sent to an unintended host. The issue is patched in `2.10.2`. `1.x` is end-of-life and will not receive a patch. Some workarounds are available. Validate the `Host` header as `uri-host [ ":" port ]` before calling `Message::parseRequest()` or legacy `parse_request()` on untrusted HTTP request data, or before deriving routing and forwarding decisions from a parsed request URI. Reject Host values containing userinfo, path, query, or fragment delimiters.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | php-guzzlehttp-psr7 Debian 12.15 (bookworm) | 2.4.5-1+deb12u1 | [DEBIAN-CVE-2026-48998](https://patchblox.com/security/data/fix/linux/debian-cve-2026-48998.md) | Jun 24, 2026 |
| Linux | php-guzzlehttp-psr7 Debian 13.5 (trixie) | 2.7.1-1+deb13u1 | [DEBIAN-CVE-2026-48998](https://patchblox.com/security/data/fix/linux/debian-cve-2026-48998.md) | Jun 24, 2026 |
| Linux | php-guzzlehttp-psr7 Debian 14 | 2.10.3-1 | [DEBIAN-CVE-2026-48998](https://patchblox.com/security/data/fix/linux/debian-cve-2026-48998.md) | Jun 24, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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