CVE-2026-45306
MEDIUMCVE-2026-45306 is a medium-severity (CVSS 6.5) CWE-706 vulnerability in pyload-ng. O3 Security confirms whether CVE-2026-45306 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
pyLoad Has Incomplete Fix for CVE-2026-33509 -storage_folder Bypass via Session Directory in pyLoad
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-45306.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-45306 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 0 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
pyload-ngReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
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
- Attacker (admin) sets
storage_folder = /tmp/pyLoad/flask - Fix does NOT block this —
/tmp/pyLoad/flasknot insidePKGDIRoruserdir - Attacker requests
GET /files/get/<victim_session_filename> send_from_directory('/tmp/pyLoad/flask', session_file)serves victim's session- Attacker uses stolen session → Account Takeover
PoC
<img width="592" height="408" alt="POC" src="https://github.com/user-attachments/assets/936b9f56-325b-437d-9edd-e0d5bb995187" />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
Impact
Authenticated admin can steal sessions of other users → Account Takeover.
Suggested Fix
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
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pyload-ng | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pyload-ng. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of pyload-ng has shipped for CVE-2026-45306 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-45306 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-45306. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-45306 in your dependencies?
O3 detects CVE-2026-45306 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.