CVE-2026-4538 PyTorch pt2 Loading deserialization
A local attacker can exploit a deserialization flaw in PyTorch's pt2 loading handler to execute arbitrary code.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-4538?
CVE-2026-4538 is a medium-severity unsafe deserialization vulnerability in PyTorch, published on 22 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A vulnerability was identified in PyTorch 2.10.0. The affected element is an unknown function of the component pt2 Loading Handler. The manipulation leads to deserialization. The attack can only be performed from a local environment. The exploit is publicly available and might be used. The project was informed of the problem early through a pull request but has not reacted yet.
Which versions are affected by CVE-2026-4538?
2 open source packages ship an affected version, including pytorch and torch. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
pytorch Bitnami | From 2.10.0 | 2.11.0 |
torch PyPI | All versions to 2.10.0 | None |
Products include Linuxfoundation Pytorch.
How do I fix CVE-2026-4538?
Upgrade pytorch to 2.11.0 or later.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2026-4538 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4538 exists.
Other vulnerabilities in PyTorch
- CVE-2024-48063 Deserialization in n/a
- CVE-2022-45907 PyTorch vulnerable to arbitrary code execution
- CVE-2025-32434 PyTorch: `torch.load` with `weights_only=True` leads to remote code execution
- CVE-2026-24747 PyTorch Vulnerable to Remote Code Execution via Untrusted Checkpoint Files
- CVE-2024-31583 Pytorch use-after-free vulnerability
Sources
Also known as BIT-pytorch-2026-4538, DEBIAN-CVE-2026-4538, ECHO-1421-5c4b-5062, GHSA-33x2-ppm4-v46v, PYSEC-2026-139, UBUNTU-CVE-2026-4538.