CVE-2021-39207

What it is

parlai is a framework for training and evaluating AI models on a variety of openly available dialogue datasets. In affected versions the package is vulnerable to YAML deserialization attack caused by unsafe loading which leads to Arbitary code execution. This security bug is patched by avoiding unsafe loader users should update to version above v1.1.0. If upgrading is not possible then users can change the Loader used to SafeLoader as a workaround. See commit 507d066ef432ea27d3e201da08009872a2f37725 for details.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. High risk of data exposure, data tampering.

Exploit odds

1.8% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-09-10 23:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 04:03 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 1.8% in the next 30 days (EPSS).
• Severity: 8.4 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-09-10 23:15 UTC

Last modified

2026-06-17 04:03 UTC

Exploit probability

1.8% · EPSS, next 30 days

Weakness

CWE-502 · Unsafe deserialization

Record status

Modified

Affected

• Facebook Parlai < 1.1.0

Attack profile CVSS 3.1 · 8.4

Attack vector

Network

Complexity

High

Privileges needed

Low

User interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

Low

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-39207.md and follow it. Check whether this project is affected by CVE-2021-39207. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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