CVE-2019-11940: Facebook Proxygen

Critical severity, CVSS 9.8. EPSS: 1.4% chance of exploitation in the next 30 days.

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.

Affected products

• Facebook Proxygen: from 0.29.0, up to and including 2017.04.03.00

Published 2019-12-04. Last modified 2026-06-17.