---
id: CVE-2026-94093
title: >-
  A security vulnerability has been detected in DLR-RM stable-baselines3 up to
  2.9.0
summary: >-
  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
  possi…
severity: medium
cvss: 6.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L'
cwe:
  - CWE-20
  - CWE-502
vendor: DLR-RM
product: stable-baselines3
affected:
  - stable-baselines3 2.0
  - stable-baselines3 2.1
  - stable-baselines3 2.2
  - stable-baselines3 2.3
  - stable-baselines3 2.4
  - stable-baselines3 2.5
  - stable-baselines3 2.6
  - stable-baselines3 2.7
  - stable-baselines3 2.8
  - stable-baselines3 2.9.0
published: '2026-09-20'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T17:19:19.420'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-94093'
references:
  - url: 'https://github.com/DLR-RM/stable-baselines3/'
    label: cna@vuldb.com
  - url: 'https://github.com/DLR-RM/stable-baselines3/issues/2281'
    label: cna@vuldb.com
  - url: 'https://vuldb.com/cve/CVE-2026-94093'
    label: cna@vuldb.com
  - url: 'https://vuldb.com/submit/952734'
    label: cna@vuldb.com
  - url: 'https://vuldb.com/vuln/408021'
    label: cna@vuldb.com
  - url: 'https://vuldb.com/vuln/408021/cti'
    label: cna@vuldb.com
  - url: 'https://github.com/DLR-RM/stable-baselines3/issues/2281'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-21T16:20:51.056033Z'
epss: 0.00259
epssPercentile: 0.17837
ingestedAt: '2026-09-20T23:28:09.528Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.