SSRF (Server-Side Request Forgery) in pyload-ng (CVE-2026-35459)
Summary
SSRF in pyload-ng (CVE-2026-35459). Confidential information can be exposed externally. Exploitable via CURLOPT_REDIR_PROTOCOLS.
Original description
The description as published by the source.
Summary
The fix for CVE-2026-33992 (GHSA-m74m-f7cr-432x) added IP validation to BaseDownloader.download() that checks the hostname of the initial download URL. However, pycurl is configured with FOLLOWLOCATION=1 and MAXREDIRS=10, causing it to automatically follow HTTP redirects. Redirect targets are never validated against the SSRF filter.
An authenticated user with ADD permission can bypass the SSRF fix by submitting a URL that redirects to an internal address.
Root Cause
The SSRF check at src/pyload/plugins/base/downloader.py:335-341 validates only the initial URL:
dl_hostname = urllib.parse.urlparse(dl_url).hostname
if is_ip_address(dl_hostname) and not is_global_address(dl_hostname):
self.fail(...)
else:
for ip in host_to_ip(dl_hostname):
if not is_global_address(ip):
self.fail(...)
After the check passes, _download() is called. pycurl is configured at src/pyload/core/network/http/http_request.py:114-115 to follow redirects:
self.c.setopt(pycurl.FOLLOWLOCATION, 1)
self.c.setopt(pycurl.MAXREDIRS, 10)
No CURLOPT_REDIR_PROTOCOLS restriction is set anywhere in HTTPRequest. Redirect targets bypass the SSRF filter entirely.
PoC
Redirect server (attacker-controlled):
from http.server import HTTPServer, BaseHTTPRequestHandler
class RedirectHandler(BaseHTTPRequestHandler):
def do_GET(self):
self.send_response(302)
self.send_header("Location",…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-35459 has been found in pyload-ng.
Attackers can target a specific entry point like CURLOPT_REDIR_PROTOCOLS over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 9.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "pyload-ng CVE-2026-35459" on the vendor's site.
CVE-2026-35459 (pyload-ng) — CWE-918 / CVSS v3 9.1
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: CURLOPT_REDIR_PROTOCOLS / attacker.com
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
SSRF (CWE-918) exists in pyload-ng. Attackers reach the vulnerable code path via CURLOPT_REDIR_PROTOCOLS without authentication.
Check the vendor advisory for the affected versions of pyload-ng. Attack surface: CURLOPT_REDIR_PROTOCOLS / attacker.com.
Severity: Critical (CVSS 9.1/10). Confidential information can be exposed externally.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'pyload-ng' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'pyload-ng' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
pyload-ngを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- package pypi.org
- web github.com
- web github.com