CVE-2016-1000111

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-03-11 · updated 2026-06-17
Weakness: CWE-425

Description

Twisted before 16.3.1 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.

Affected products

twisted: before 16.3.1 — fixed in 16.3.1

How to fix

Upgrade to a fixed version: twisted 16.3.1. Check the vendor advisory for mitigations.

References

http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2016-3090545.html
https://twistedmatrix.com/pipermail/twisted-web/2016-August/005268.html
https://twistedmatrix.com/trac/ticket/8623
https://www.openwall.com/lists/oss-security/2016/07/18/6
http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2016-3090545.html
https://twistedmatrix.com/pipermail/twisted-web/2016-August/005268.html
https://twistedmatrix.com/trac/ticket/8623
https://www.openwall.com/lists/oss-security/2016/07/18/6

Get alerted when CVE-2016-1000111 or the next vulnerability affects your stack