CVE-2026-45306

The fix for CVE-2026-33509 prevents setting storage_folder inside PKGDIR or userdir, but does NOT protect the Flask session directory (/tmp/pyLoad/flask). An authenticated attacker can set storage_folder to the session directory and download session files of other users via /files/get/, leading to account takeover.

Details

The fix in src/pyload/core/api/__init__.py:

directories = [PKGDIR, userdir]
if any(directories[0].startswith(d) for d in directories[1:]):
    return  # blocked

But the Flask session directory is:

session_storage_path = os.path.join(api.get_cachedir(), "flask")
# = /tmp/pyLoad/flask  ← NOT blocked by fix

Attack Chain

1. Attacker (admin) sets storage_folder = /tmp/pyLoad/flask
2. Fix does NOT block this, /tmp/pyLoad/flask not inside PKGDIR or userdir
3. Attacker requests GET /files/get/<victim_session_filename>
4. send_from_directory('/tmp/pyLoad/flask', session_file) serves victim's session
5. Attacker uses stolen session → Account Takeover

PoC

import os

PKGDIR = "/usr/lib/python3/dist-packages/pyload"
userdir = os.path.expanduser("~/.pyload")
session_dir = "/tmp/pyLoad/flask"

correct_case = lambda x: x
directories = [
    correct_case(os.path.join(os.path.realpath(d), ""))
    for d in [session_dir, PKGDIR, userdir]
]
blocked = any(directories[0].startswith(d) for d in directories[1:])

print(f"Fix blocks session_dir: {blocked}")
# Output: Fix blocks session_dir: False  ← BYPASS CONFIRMED

Authenticated admin can steal sessions of other users → Account Takeover.

CVE-2026-45306 has a CVSS score of 6.5 (Medium). The vector is network-reachable, high privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.

Kodem intelligence

blocked_dirs = [PKGDIR, userdir, api.get_cachedir()]
directories = [
    os.path.join(os.path.realpath(d), "")
    for d in [value] + blocked_dirs
]
if any(directories[0].startswith(d) for d in directories[1:]):
    return

1. What is CVE-2026-45306? CVE-2026-45306 is a medium-severity security vulnerability in pyload-ng (pip), affecting versions <= 0.5.0b3.dev99. No fixed version is listed yet.
2. How severe is CVE-2026-45306? CVE-2026-45306 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of pyload-ng are affected by CVE-2026-45306? pyload-ng (pip) versions <= 0.5.0b3.dev99 is affected.
4. Is there a fix for CVE-2026-45306? No fixed version is listed for CVE-2026-45306 yet. Monitor the advisory for updates and apply mitigations in the interim.
5. Is CVE-2026-45306 exploitable, and should I be worried? Whether CVE-2026-45306 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-45306 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.