# CVE-2025-3730: PyTorch LossCTC.cpp torch.nn.functional.ctc_loss denial of service

> A local attacker can cause a denial of service in PyTorch via the ctc_loss function, requiring a patch to mitigate.

- **Severity:** Medium 4.8 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **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:** Yes
- **Published:** 16 Apr 2025
- **Updated:** 22 May 2025
- **Also known as:** AZL-60500, AZL-60577, BIT-pytorch-2025-3730, DEBIAN-CVE-2025-3730, ECHO-60ee-2760-44eb, GHSA-887c-mr87-cxwp, PYSEC-2026-1970, UBUNTU-CVE-2025-3730

## What is CVE-2025-3730?

CVE-2025-3730 is a medium-severity denial of service vulnerability in PyTorch, published on 16 Apr 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability, which was classified as problematic, was found in PyTorch 2.6.0. Affected is the function torch.nn.functional.ctc_loss of the file aten/src/ATen/native/LossCTC.cpp. The manipulation leads to denial of service. An attack has to be approached locally. The exploit has been disclosed to the public and may be used. The real existence of this vulnerability is still doubted at the moment. The name of the patch is 46fc5d8e360127361211cb237d5f9eef0223e567. It is recommended to apply a patch to fix this issue. The security policy of the project warns to use unknown models which might establish malicious effects.

Weakness: CWE-404 (Improper Resource Shutdown or Release)

## Which versions are affected by CVE-2025-3730?

4 open source packages ship an affected version, including pytorch and torch. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `pytorch` | Bitnami | From 2.6.0 | 2.7.0 |
| `torch` | PyPI | All versions | 2.8.0 |
| `torch` | PyPI | All versions | 2.8.0 |
| `torch` | PyPI | All versions | 2.8.0 |

Products: Linuxfoundation Pytorch.

## How do I fix CVE-2025-3730?

Upgrade pytorch to 2.7.0 or later.

## Is CVE-2025-3730 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-3730 exists.

## Other vulnerabilities in PyTorch

- [CVE-2024-48063](https://insights.sbomify.com/CVE-2024-48063/): Deserialization in n/a (critical 9.8)
- [CVE-2022-45907](https://insights.sbomify.com/CVE-2022-45907/): PyTorch vulnerable to arbitrary code execution (critical 9.8)
- [CVE-2025-32434](https://insights.sbomify.com/CVE-2025-32434/): PyTorch: `torch.load` with `weights_only=True` leads to remote code execution (critical 9.3)
- [CVE-2026-24747](https://insights.sbomify.com/CVE-2026-24747/): PyTorch Vulnerable to Remote Code Execution via Untrusted Checkpoint Files (high 8.8)
- [CVE-2024-31583](https://insights.sbomify.com/CVE-2024-31583/): Pytorch use-after-free vulnerability (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-3730 and fix it if it is affected.

What it is: CVE-2025-3730 is a medium-severity denial of service vulnerability in PyTorch, published on 16 Apr 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-3730 exists.

Affected packages and fixed versions:
- pytorch (Bitnami): affected from 2.6.0; fixed in 2.7.0
- torch (PyPI): affected all versions; fixed in 2.8.0
- torch (PyPI): affected all versions; fixed in 2.8.0
- torch (PyPI): affected all versions; fixed in 2.8.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-3730/ (Markdown: https://insights.sbomify.com/CVE-2025-3730/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-3730
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-3730
- OSV: https://osv.dev/vulnerability/CVE-2025-3730

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-3730/
Summaries are generated and may contain mistakes; the official description above is the record.