Vulnerability record · CVE-2016-1000109 · published 19 February 2020

CVE-2016-1000109: Facebook hhvm vulnerability

Facebook · Hhvm

HHVM does not attempt to address RFC 3875 section 4.1.18 namespace conflicts and therefore does not protect CGI applications from the presence of untrusted client data in the HTTP_PROXY environment variable, which might allow remote attackers to redirect a CGI application's outbound HTTP traffic to an arbitrary proxy server via a crafted Proxy header in an HTTP request, aka an "httpoxy" issue. This issue affects HHVM versions prior to 3.9.6, all versions between 3.10.0 and 3.12.4 (inclusive), and all versions between 3.13.0 and 3.14.2 (inclusive).

5.3 CVSS 3.1 Medium EPSS 5.1% · top 8.0% CWE-665 · CWE-665

5.3CVSS 3.1 base score, v2 5.0

5.1%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

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

Affected products

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

Hhvm Facebook

References

Link	Tags
https://github.com/facebook/hhvm/commit/423b4b719afd5ef4e6e19d8447fbf7b6bc0d0a25	PatchThird Party Advisory
https://httpoxy.org/	ExploitMitigationThird Party Advisory
https://www.facebook.com/security/advisories/cve-2016-1000109	Third Party Advisory
https://github.com/facebook/hhvm/commit/423b4b719afd5ef4e6e19d8447fbf7b6bc0d0a25	PatchThird Party Advisory
https://httpoxy.org/	ExploitMitigationThird Party Advisory
https://www.facebook.com/security/advisories/cve-2016-1000109	Third Party Advisory

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

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Source: NIST National Vulnerability Database (record CVE-2016-1000109), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.