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Vulnerability record · CVE-2021-24036 · published 23 July 2021

CVE-2021-24036: Facebook folly heap-based buffer overflow vulnerability

Facebook · Folly

Passing an attacker controlled size when creating an IOBuf could cause integer overflow, leading to an out of bounds write on the heap with the possibility of remote code execution. This issue affects versions of folly prior to v2021.07.22.00. This issue affects HHVM versions prior to 4.80.5, all versions between 4.81.0 and 4.102.1, all versions between 4.103.0 and 4.113.0, and versions 4.114.0, 4.115.0, 4.116.0, 4.117.0, 4.118.0 and 4.118.1.

9.8 CVSS 3.1 Critical EPSS 3.3% · top 12.0% CWE-122 · Heap-based buffer overflowCWE-190 · Integer overflow
9.8CVSS 3.1 base score, v2 7.5
3.3%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
6References
17 Jun 2026Last modified by NVD

Description

Passing an attacker controlled size when creating an IOBuf could cause integer overflow, leading to an out of bounds write on the heap with the possibility of remote code execution. This issue affects versions of folly prior to v2021.07.22.00. This issue affects HHVM versions prior to 4.80.5, all versions between 4.81.0 and 4.102.1, all versions between 4.103.0 and 4.113.0, and versions 4.114.0, 4.115.0, 4.116.0, 4.117.0, 4.118.0 and 4.118.1.

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

Affected products

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

References

LinkTags
https://github.com/facebook/folly/commit/4f304af1411e68851bdd00ef6140e9de4616f7d3 PatchThird Party Advisory
https://hhvm.com/blog/2021/07/20/security-update.html ProductVendor Advisory
https://www.facebook.com/security/advisories/cve-2021-24036 Vendor Advisory
https://github.com/facebook/folly/commit/4f304af1411e68851bdd00ef6140e9de4616f7d3 PatchThird Party Advisory
https://hhvm.com/blog/2021/07/20/security-update.html ProductVendor Advisory
https://www.facebook.com/security/advisories/cve-2021-24036 Vendor Advisory

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Source: NIST National Vulnerability Database (record CVE-2021-24036), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.