CVE-2026-33511

CRITICAL

pyload-ng: Authentication Bypass via Host Header Injection in ClickNLoad

Title source: cna
STIX 2.1

Description

pyLoad is a free and open-source download manager written in Python. From version 0.4.20 to before version 0.5.0b3.dev97, the local_check decorator in pyLoad's ClickNLoad feature can be bypassed by any remote attacker through HTTP Host header spoofing. This allows unauthenticated remote users to access localhost-restricted endpoints, enabling them to inject arbitrary downloads, write files to the storage directory, and execute JavaScript code. This issue has been patched in version 0.5.0b3.dev97.

References (1)

Core 1
Core References

Scores

CVSS v3 9.8
EPSS 0.0018
EPSS Percentile 39.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-639
Status published
Products (3)
pyload/pyload < 0.4.20
pyload/pyload >= 0.4.20, < 0.5.0b3.dev97
pyload-ng_project/pyload-ng 0.5.0a5.dev528 - 0.5.0b3.dev97
Published Mar 24, 2026
Tracked Since Mar 25, 2026