---
id: CVE-2026-48737
title: pyLoad is a free and open-source download manager written in Python
summary: >-
  pyLoad is a free and open-source download manager written in Python. Prior to
  0.5.0b3.dev101, is_global_address in src/pyload/core/utils/web/check.py relies
  on Python's global-address classification without examining IPv4 destinations
  em…
severity: medium
cvss: 4.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:L'
cwe:
  - CWE-918
vendor: pyload
product: pyload
affected:
  - pyload < 0.5.0b3.dev101
published: '2026-09-15'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T17:17:18.907'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-48737'
references:
  - url: >-
      https://github.com/pyload/pyload/commit/ba7491046b2d430732be490913e4cbf1f1e899c2
    label: security-advisories@github.com
  - url: 'https://github.com/pyload/pyload/security/advisories/GHSA-m5x5-28jr-gpjj'
    label: security-advisories@github.com
  - url: 'https://github.com/pyload/pyload/security/advisories/GHSA-m5x5-28jr-gpjj'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://github.com/advisories/GHSA-m5x5-28jr-gpjj'
tags:
  - nvd
  - cve.org
  - ghsa
  - pip
  - exploit-available
aliases:
  - GHSA-m5x5-28jr-gpjj
ecosystem: pip
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-16T16:04:41.559990Z'
ingestedAt: '2026-07-09T13:51:05.216Z'
epss: 0.00289
epssPercentile: 0.19072
---

## Overview

pyLoad is a free and open-source download manager written in Python. Prior to 0.5.0b3.dev101, is_global_address in src/pyload/core/utils/web/check.py relies on Python's global-address classification without examining IPv4 destinations embedded in 6to4 or NAT64 IPv6 addresses. A low-privileged user can submit an IPv6 literal through parse_urls to the pre-resolution is_global_host guard. Because host_to_ip is pinned to AF_INET, that guard does not evaluate a hostname's AAAA result. Separately, curl resolves hostnames before the pycurl PREREQFUNC in src/pyload/core/network/http/http_request.py applies the same vulnerable is_global_address check to the actual connection address, so a transition-form AAAA result can be permitted even when it terminates at an embedded loopback, private, CGNAT, or link-local IPv4 address. Exploitation requires the pyLoad host to route the applicable transition mechanism, including 6to4 on affected Python 3.9 through 3.11 deployments or NAT64 on a network with a NAT64 gateway. Successful exploitation can enable internal-network reconnaissance, timing-based confirmation, limited service disruption, or cloud metadata disclosure where the wrapped address is routable. This issue is fixed in version 0.5.0b3.dev101.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-48737)

Affected packages:

- `pyload-ng <= 0.5.0b3.dev100`

Source: https://github.com/advisories/GHSA-m5x5-28jr-gpjj