CVE-2019-11940

Name: CVE-2019-11940
Creator: NVD / NIST
Published: 2019-12-04T17:16:43.773+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.36%

Last modified Jun 17, 2026

CVE-2019-11940 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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.. EPSS estimates a 1.36% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

1.36%

68.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Facebook	Proxygen	>= 0.29.0, <= 2017.04.03.00

References

https://github.com/facebook/proxygen/commit/f43b134cc5c19d8532e7fb670a1c02e85f7a8d4fPatch, Third Party Advisory
https://www.facebook.com/security/advisories/cve-2019-11940Third Party Advisory
https://github.com/facebook/proxygen/commit/f43b134cc5c19d8532e7fb670a1c02e85f7a8d4fPatch, Third Party Advisory
https://www.facebook.com/security/advisories/cve-2019-11940Third Party Advisory

Timeline

Published: Dec 4, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-11940?

How severe is CVE-2019-11940?

CVE-2019-11940 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.36% probability of exploitation in the next 30 days.

How do I fix CVE-2019-11940?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-11940?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST