LiveActive security incident?Get immediate response
CVE Record

CVE-2016-1000109: HHVM does not attempt to address RFC 3875 section 4.1.18 namespace conflicts and therefore does not protect...

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).

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This HHVM flaw is an httpoxy issue: a remote request can supply a Proxy header that becomes trusted HTTP_PROXY environment data for CGI applications. If an affected application makes outbound HTTP requests, an attacker may redirect that traffic through a proxy they control.

Executive priority

Treat as a targeted remediation item for legacy HHVM and CGI environments. It is not KEV-listed in the supplied data, but exposed affected services can risk outbound traffic interception or redirection.

Technical view

HHVM did not handle RFC 3875 section 4.1.18 namespace conflicts for HTTP_PROXY. A crafted Proxy request header could influence CGI application environment variables, allowing outbound HTTP traffic from the CGI application to be routed through an arbitrary proxy.

Likely exposure

Exposure is limited to HHVM deployments running affected versions with CGI applications that make outbound HTTP requests and rely on proxy-related environment variables. Affected ranges are before 3.9.6, 3.10.0 through 3.12.4, and 3.13.0 through 3.14.2.

Exploitation context

The provided sources do not show CISA KEV listing or confirmed active exploitation. The attack is remotely reachable when an exposed CGI path accepts crafted HTTP headers and the backend makes outbound HTTP requests afterward.

Researcher notes

Focus validation on the header-to-environment-variable boundary and outbound HTTP client behavior. Avoid assuming broad HHVM exposure: the issue matters when CGI behavior, affected HHVM versions, and outbound proxy-aware requests intersect.

Mitigation direction

  • Upgrade HHVM to a release outside the listed affected version ranges.
  • Review Facebook/HHVM advisory guidance before choosing a target fixed version.
  • Filter, unset, or ignore HTTP_PROXY in CGI application environments where vendor guidance recommends it.
  • Inventory CGI-facing HHVM services that make outbound HTTP requests.
  • Retest after upgrades or configuration changes.

Validation and detection

  • Confirm all HHVM versions in production and staging inventories.
  • Identify CGI applications served by HHVM that perform outbound HTTP requests.
  • Check whether incoming Proxy headers can reach CGI environment handling.
  • Review server or application controls that strip HTTP_PROXY from CGI environments.
  • Verify upgraded HHVM builds are outside the affected ranges.
Prepared
Confidence
high
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cve · low confidence lookup

CVE-2016-1000109 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.