CVE-2026-33511Public exploitNetwork attack vector

Unauthenticated endpoint access via trusted Host header

Published Mar 24, 2026 · Updated Mar 24, 2026

Authentication bypass in pyLoad 0.4.20 through 0.5.0b3.dev96 allows remote attackers to access local-only ClickNLoad endpoints. The local_check decorator trusts the client-controlled HTTP Host header as an alternative to the server-controlled remote address. A network-exposed instance with ClickNLoad enabled accepts a spoofed localhost Host value, enabling download injection, storage-directory writes, and sandboxed JavaScript execution.

CVSS severity8.8
High
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in pyLoad 0.4.20 through 0.5.0b3.dev96 allows remote attackers to access local-only ClickNLoad endpoints. The local_check decorator trusts the client-controlled HTTP Host header as an alternative to the server-controlled remote address. A network-exposed instance with ClickNLoad enabled accepts a spoofed localhost Host value, enabling download injection, storage-directory writes, and sandboxed JavaScript execution.

The record

CVE
CVE-2026-33511
Published
Mar 24, 2026
Updated
Mar 24, 2026
Vendor
pyLoad
Product
pyLoad
Classifications
CWE-639, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 24, 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=>= 0.4.20, < 0.5.0b3.dev97

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

pyLoad · pyLoadversion=>= 0.4.20, < 0.5.0b3.dev97

Published CVSS scores

8.8GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:L/SC:N/SI:L/SA:N
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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 exploitPublished

Weakness, pattern, technique

CWE-639Authorization Bypass Through User-Controlled Key
T1190Exploit Public-Facing Application

Public exploit references

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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