CVE-2026-50188Network attack vector

Remote-service header override via newline injection

Published Jul 9, 2026 · Updated Jul 9, 2026

HTTP request header injection in Content Folder Kirby before 4.9.4 and 5.0.0 through 5.4.3 allows remote attackers to override outgoing headers. The Http Remote fetch method appends header values to CURLOPT_HTTPHEADER without stripping carriage returns or line feeds, causing cURL to send injected lines as separate headers. Exploitation requires custom code, a plugin, or an integration to place attacker-controlled data in a header value; the default installation is unaffected, and the receiving service suffers integrity impact.

CVSS severity6.9
Medium
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

HTTP request header injection in Content Folder Kirby before 4.9.4 and 5.0.0 through 5.4.3 allows remote attackers to override outgoing headers. The Http Remote fetch method appends header values to CURLOPT_HTTPHEADER without stripping carriage returns or line feeds, causing cURL to send injected lines as separate headers. Exploitation requires custom code, a plugin, or an integration to place attacker-controlled data in a header value; the default installation is unaffected, and the receiving service suffers integrity impact.

The record

CVE
CVE-2026-50188
Published
Jul 9, 2026
Updated
Jul 9, 2026
Vendor
Content Folder
Product
Kirby
Classifications
CWE-93, CWE-113, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 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=< 4.9.4
  2. Affected versionversion=>= 5.0.0, < 5.4.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Content Folder · Kirbyversion=< 4.9.4; version=>= 5.0.0, < 5.4.4

Published CVSS scores

6.9GitHubCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:H/SA: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-93Improper Neutralization of CRLF Sequences ('CRLF Injection')
CWE-113Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
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

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Your stack

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