CVE-2016-1000109
MEDIUMEPSS 92th pctlDescription
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).
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Exploit Intelligence
High risk: more likely to be exploited than 92% of all known CVEs.
References
Related Vulnerabilities
Other CWE-665 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2022-0847 | High | 7.8 | 90% | KEV | Fix |
| CVE-2022-22719 | High | 7.5 | 70% | - | Fix |
| CVE-2020-28019 | High | 7.5 | 62% | - | Fix |
| CVE-2022-46164 | Critical | 9.4 | 49% | - | Fix |
| CVE-2022-37128 | Critical | 9.8 | 21% | - | - |
| CVE-2019-14271 | Critical | 9.8 | 19% | - | Fix |
Common questions
How do I fix CVE-2016-1000109?
Upgrade hhvm to 3.9.6 or later.
Is CVE-2016-1000109 being actively exploited?
Not that we know of. CVE-2016-1000109 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 5.1% is the estimated probability that it will be exploited in the next 30 days. That is higher than 92% of all scored CVEs.
How severe is CVE-2016-1000109?
CVE-2016-1000109 has a CVSS v3 base score of 5.3, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2016-1000109 affect?
Published advisories record a fix for hhvm (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-17.