CVE-2026-61900Network attack vector

Unauthenticated file writes via standalone upload handler

Published Jul 20, 2026 · Updated Jul 20, 2026

Unrestricted file upload in Arno Betz jDownloads 4.1.0 through 4.1.5 allows remote attackers to write files via HTTP. The standalone upload-handler.php script bypasses Joomla sessions, CSRF validation, permissions, and the extension's upload blacklist. It blocks .php by default, but stored files remain web-readable and can fill disk; code execution requires secondary-extension handling or widened executable types.

CVSS severity10.0
Critical
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unrestricted file upload in Arno Betz jDownloads 4.1.0 through 4.1.5 allows remote attackers to write files via HTTP. The standalone upload-handler.php script bypasses Joomla sessions, CSRF validation, permissions, and the extension's upload blacklist. It blocks .php by default, but stored files remain web-readable and can fill disk; code execution requires secondary-extension handling or widened executable types.

The record

CVE
CVE-2026-61900
Published
Jul 20, 2026
Updated
Jul 20, 2026
Vendor
jDownloads
Product
jDownloads
Classifications
CWE-434, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 20, 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=4.1.0-4.1.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

jDownloads · jDownloadsversion=4.1.0-4.1.5

Published CVSS scores

10.0Joomla! ProjectCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
8.8mySites.guruCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/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-434Unrestricted Upload of File with Dangerous Type
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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