CVE-2026-48998Network attack vector

SSRF via malformed Host authority reinterpretation

Published Jun 11, 2026 · Updated Jun 11, 2026

Improper Host validation in Guzzle PSR-7 before 2.10.2 allows remote attackers to redirect forwarding decisions via malformed headers. Message::parseRequest() and ServerRequest URI construction accept Host values containing authority delimiters, so @ can be reinterpreted as URI userinfo and host. Exposure requires an application to parse attacker-controlled inbound requests and trust the derived URI host for routing, allow-list, credential-selection, or forwarding decisions, which can send requests or credentials to an unintended host.

CVSS severity5.3
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper Host validation in Guzzle PSR-7 before 2.10.2 allows remote attackers to redirect forwarding decisions via malformed headers. Message::parseRequest() and ServerRequest URI construction accept Host values containing authority delimiters, so @ can be reinterpreted as URI userinfo and host. Exposure requires an application to parse attacker-controlled inbound requests and trust the derived URI host for routing, allow-list, credential-selection, or forwarding decisions, which can send requests or credentials to an unintended host.

The record

CVE
CVE-2026-48998
Published
Jun 11, 2026
Updated
Jun 11, 2026
Vendor
Guzzle
Product
Guzzle PSR-7
Classifications
CWE-918, CWE-20, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.10.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Guzzle · Guzzle PSR-7version=< 2.10.2

Published CVSS scores

5.3GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
CWE-20Improper Input Validation
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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