# CVE-2026-94093: DLR-RM stable-baselines3 save_util.py VecNormalize.load deserialization

> Remote attackers can execute arbitrary code via unsafe pickle deserialization in stable-baselines3 load functions, affecting users of this reinforcement learning library.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 20 Sep 2026
- **Updated:** 21 Sep 2026
- **Also known as:** GHSA-rh54-3493-vqgc

## What is CVE-2026-94093?

CVE-2026-94093 is a medium-severity unsafe deserialization vulnerability in DLR-RM stable-baselines3, published on 20 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

A security vulnerability has been detected in DLR-RM stable-baselines3 up to 2.9.0. This affects the function PPO.load/load_replay_buffer/VecNormalize.load of the file save_util.py. Such manipulation leads to deserialization. It is possible to launch the attack remotely. The exploit has been disclosed publicly and may be used. In v2.9.0 the PyTorch tensor load path is hardened (weights_only=True), but that hardening was later reverted on master via PR #1913 "Hotfix: revert loading with weights_only=True" [blocked] to fix PyTorch 1.13 compat - so even the one "safe" path is inconsistent across versions. #2281 was closed as a duplicate of #1831 since both are unsafe pickle deserialization - but #1831's fix (PR #41) only gated the Hugging Face Hub loader in the separate huggingface_sb3 package. This finding covers the core stable_baselines3 load APIs (PPO.load, load_replay_buffer, VecNormalize.load), which have no safe mode or gate and remained exploitable in v2.9.0 until the outstanding hardening (PR #2264) ships.

Weakness: CWE-502 (Deserialization of Untrusted Data), CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2026-94093?


## How do I fix CVE-2026-94093?

No fix has been published for CVE-2026-94093 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-94093 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-94093 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-94093 and fix it if it is affected.

What it is: CVE-2026-94093 is a medium-severity unsafe deserialization vulnerability in DLR-RM stable-baselines3, published on 20 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-94093 exists.

Affected product: DLR-RM stable-baselines3. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-94093/ (Markdown: https://insights.sbomify.com/CVE-2026-94093/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-94093
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-94093
- OSV: https://osv.dev/vulnerability/CVE-2026-94093

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-94093/
Summaries are generated and may contain mistakes; the official description above is the record.