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Vulnerability record · CVE-2019-11940 · published 4 December 2019

CVE-2019-11940: Facebook proxygen use after free vulnerability

Facebook · Proxygen

In the course of decompressing HPACK inside the HTTP2 protocol, an unexpected sequence of header table resize operations can place the header table into a corrupted state, leading to a use-after-free condition and undefined behavior. This issue affects Proxygen from v0.29.0 until v2017.04.03.00.

9.8 CVSS 3.1 Critical EPSS 1.4% · top 29.3% CWE-416 · Use after free
9.8CVSS 3.1 base score, v2 7.5
1.4%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References
17 Jun 2026Last modified by NVD

Description

In the course of decompressing HPACK inside the HTTP2 protocol, an unexpected sequence of header table resize operations can place the header table into a corrupted state, leading to a use-after-free condition and undefined behavior. This issue affects Proxygen from v0.29.0 until v2017.04.03.00.

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
https://github.com/facebook/proxygen/commit/f43b134cc5c19d8532e7fb670a1c02e85f7a8d4f PatchThird Party Advisory
https://www.facebook.com/security/advisories/cve-2019-11940 Third Party Advisory
https://github.com/facebook/proxygen/commit/f43b134cc5c19d8532e7fb670a1c02e85f7a8d4f PatchThird Party Advisory
https://www.facebook.com/security/advisories/cve-2019-11940 Third Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2019-11940), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.