CVE-2026-49214Network attack vector

Attacker-controlled headers via unvalidated URI host

Published Jun 11, 2026 · Updated Jun 11, 2026

CRLF injection in Guzzle PSR-7 before 2.10.2 allows remote attackers to add HTTP headers through a crafted URI host. Message::toString() copies an unvalidated host containing control characters into the Host line when serializing a raw HTTP/1.x request. Exploitation requires attacker-controlled URLs, raw serialization without an explicit Host header, and a downstream component that accepts the malformed request; standard Guzzle client APIs are not affected.

CVSS severity5.3
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

CRLF injection in Guzzle PSR-7 before 2.10.2 allows remote attackers to add HTTP headers through a crafted URI host. Message::toString() copies an unvalidated host containing control characters into the Host line when serializing a raw HTTP/1.x request. Exploitation requires attacker-controlled URLs, raw serialization without an explicit Host header, and a downstream component that accepts the malformed request; standard Guzzle client APIs are not affected.

The record

CVE
CVE-2026-49214
Published
Jun 11, 2026
Updated
Jun 11, 2026
Vendor
Guzzle
Product
Guzzle PSR-7
Classifications
CWE-113, CWE-93, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

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:N/I:L/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-113Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
CWE-93Improper Neutralization of CRLF Sequences ('CRLF Injection')
CWE-20Improper Input Validation
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo