CVE-2021-43811

HIGH

Sockeye < 2.3.24 - Remote Code Execution via Unsafe YAML Loading

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2021-43811. PoCs published by s-index.

AI-analyzed exploit summary This PoC demonstrates a YAML deserialization vulnerability in Sockeye (CVE-2021-43811), where unsafe YAML loading allows arbitrary code execution via a malicious config file. The exploit uses Python's YAML parser to trigger command execution (e.g., `cat /etc/passwd`).

Description

Sockeye is an open-source sequence-to-sequence framework for Neural Machine Translation built on PyTorch. Sockeye uses YAML to store model and data configurations on disk. Versions below 2.3.24 use unsafe YAML loading, which can be made to execute arbitrary code embedded in config files. An attacker can add malicious code to the config file of a trained model and attempt to convince users to download and run it. If users run the model, the embedded code will run locally. The issue is fixed in version 2.3.24.

Exploits (1)

nomisec WORKING POC 2 stars
by s-index · poc
https://github.com/s-index/CVE-2021-43811

This PoC demonstrates a YAML deserialization vulnerability in Sockeye (CVE-2021-43811), where unsafe YAML loading allows arbitrary code execution via a malicious config file. The exploit uses Python's YAML parser to trigger command execution (e.g., `cat /etc/passwd`).

Classification
Working Poc 100%
Attack Type
Rce
Complexity
Trivial
Reliability
Reliable
Target: awslabs/sockeye < 2.3.24
No auth needed
Prerequisites: Victim must load a malicious YAML config file into Sockeye
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (3)

Core 3
Core References
Patch, Third Party Advisory x_refsource_misc
https://github.com/awslabs/sockeye/pull/964
Release Notes, Third Party Advisory x_refsource_misc
https://github.com/awslabs/sockeye/releases/tag/2.3.24

Scores

CVSS v3 7.8
EPSS 0.0872
EPSS Percentile 92.7%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Details

CWE
CWE-94
Status published
Products (2)
amazon/sockeye < 2.3.24
pypi/sockeye 0 - 2.3.24PyPI
Published Dec 08, 2021
Tracked Since Feb 18, 2026