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).
Conclusion & alert: CVE-2016-1000109 is rated High Exploit Risk (65.2/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.59%). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
| EDB-ID | Source | Kind | Published | Link |
|---|---|---|---|---|
| — | nvd_ref | exploit_tag | Exploit-DB ↗ |
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2025-12-28 | 1.03% | 1.59% | +0.56% |
| 2 | 2025-12-27 | 1.59% | 1.03% | -0.56% |
| 3 | 2025-10-28 | — | 1.59% | — |
Full EPSS history (15 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 5.3 | 3.1 | MEDIUM |
|
3.9 | 1.4 | [email protected] |
| 5.0 | 2.0 | MEDIUM |
|
10.0 | 2.9 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
ubuntu
|
medium | CVE-2016-1000109 medium priority: Ubuntu including 1 source packages (hhvm), 21 status rows across 21 suites (artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, mantic, noble, oracular, plucky, precise, questing, trusty, upstream, xenial, yakkety, zesty): DNE 16, not-affected 3, needed 1, released 1. | https://ubuntu.com/security/CVE-2016-1000109 |
| URL | Tags |
|---|---|
| https://github.com/facebook/hhvm/commit/423b4b719afd5ef4e6e19d8447fbf7b6bc0d0a25 | Patch Third Party Advisory |
| https://httpoxy.org/ | Exploit Mitigation Third Party Advisory |
| https://www.facebook.com/security/advisories/cve-2016-1000109 | Third Party Advisory |