CVE-2026-35464 pyLoad: Unprotected storage_folder enables arbitrary file write to Flask session store and code execution (Incomplete fix for CVE-2026-33509)
A user with settings permissions can redirect downloads to the session store to plant a malicious pickle payload, leading to arbitrary code execution.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-35464?
CVE-2026-35464 is a high-severity unsafe deserialization vulnerability in pyload, published on 7 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
pyLoad is a free and open-source download manager written in Python. The fix for CVE-2026-33509 added an ADMIN_ONLY_OPTIONS set to block non-admin users from modifying security-critical config options. The storage_folder option is not in this set and passes the existing path restriction because the Flask session directory is outside both PKGDIR and userdir. A user with SETTINGS and ADD permissions can redirect downloads to the Flask filesystem session store, plant a malicious pickle payload as a predictable session file, and trigger arbitrary code execution when any HTTP request arrives with the corresponding session cookie. This vulnerability is fixed with commit c4cf995a2803bdbe388addfc2b0f323277efc0e1.
Which versions are affected by CVE-2026-35464?
3 open source packages ship an affected version, including pyload-ng. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
pyload-ng PyPI | All versions to 0.5.0b3 | None |
pyload-ng PyPI | All versions to 0.5.0b3 | None |
pyload-ng PyPI | All versions to 0.5.0b3 | None |
Products include Pyload Pyload.
How do I fix CVE-2026-35464?
No fix has been published for CVE-2026-35464 yet. Limit exposure of the affected software until one is available.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2026-35464 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-35464 exists.
Other vulnerabilities in pyload
- CVE-2023-0297 Code Injection in pyload/pyload
- CVE-2026-33992 pyLoad: Server-Side Request Forgery via Download Link Submission Enables Cloud Metadata Exfiltration
- CVE-2024-47821 pyLoad vulnerable to remote code execution by download to /.pyload/scripts using /flashgot API
- CVE-2024-32880 pyLoad allows upload to arbitrary folder lead to RCE
- CVE-2026-41133 pyLoad has Stale Session Privilege After Role/Permission Change (Privilege Revocation Bypass)
Sources
Also known as GHSA-4744-96p5-mp2j, PYSEC-2026-2989.