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Vulnerability record · CVE-2021-24040 · published 10 September 2021

CVE-2021-24040: Facebook parlai deserialization of untrusted data vulnerability

Facebook · Parlai

Due to use of unsafe YAML deserialization logic, an attacker with the ability to modify local YAML configuration files could provide malicious input, resulting in remote code execution or similar risks. This issue affects ParlAI prior to v1.1.0.

9.8 CVSS 3.1 Critical EPSS 17% · top 3.0% CWE-502 · Deserialization of untrusted data
9.8CVSS 3.1 base score, v2 7.5
17%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
6References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

Due to use of unsafe YAML deserialization logic, an attacker with the ability to modify local YAML configuration files could provide malicious input, resulting in remote code execution or similar risks. This issue affects ParlAI prior to v1.1.0.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://packetstormsecurity.com/files/164136/Facebook-ParlAI-1.0.0-Code-Execution-Deserialization.html ExploitThird Party AdvisoryVDB Entry
https://github.com/facebookresearch/ParlAI/releases/tag/v1.1.0 Release NotesThird Party Advisory
https://github.com/facebookresearch/ParlAI/security/advisories/GHSA-m87f-9fvv-2mgg PatchThird Party Advisory
http://packetstormsecurity.com/files/164136/Facebook-ParlAI-1.0.0-Code-Execution-Deserialization.html ExploitThird Party AdvisoryVDB Entry
https://github.com/facebookresearch/ParlAI/releases/tag/v1.1.0 Release NotesThird Party Advisory
https://github.com/facebookresearch/ParlAI/security/advisories/GHSA-m87f-9fvv-2mgg PatchThird Party Advisory

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Source: NIST National Vulnerability Database (record CVE-2021-24040), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.